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Observations for 2026 September 02


The wait for the morning Grand eruption was mostly uneventful. There was a short West Triplet eruption followed by a full length eruption about an hour later. Grand had its One Burst Eruption immediatly after that second West Triplet eruption ended.

2026-Sep-02 : 10:19:23 G1C

 10:19:22	Boop	-0m01s
 10:19:23	B1	--- d=10m14s
 10:20:20	Turban	0m57s
 10:22:10	Vent	2m47s
 10:29:37	P1	10m14s
 10:30:09	Drain	10m46s
Vent & Turban continue

				     	ΣD=10m14s
	* * * * *
 08:15:48			d=03m45s	
 08:38:27	Int: 22m39s	d=04m36s	
 08:40:43	West Triplet
 08:59:03	Int: 20m36s	d=04m08s	
 09:17:56	Int: 18m53s	d=03m53s	
 09:36:16	Int: 18m20s	d=03m49s	
 09:42:25	West Triplet
 09:54:42	Int: 18m26s	d=03m54s	
		      Grand: 24m41s

From there it was time to visit the Bijou Cage. About twenty minutes after I arrived, we got a large Mastiff surge, with a height of two or three meters. Bijou shut down for about three minutes, with water in Mastiff rising to within 20cm of the rim. There was only some weak sputtering from the Southwest Vents, but Feather did show water briefly.

About 20 minutes later I noticed water in Emerald's vent. That lasted only a few seconds, and wasn't repeated, but was the first time this trip I saw or heard of water there. Back in June I saw Emerald periodically overflow for about one minute in eight.

About an hour after the bathtub Mastiff had another surge, and a second an hour after that. Otherwise nothing much happened. (The next Bijou pause and Mastiff bathtub was in the early evening, about six hours after this earlier pause and bathtub.)

It was a windy day, so I was dressed for cold as I headed out in the early evening. There was a Turban Delay Interval lasting almost 31 minutes. After that, at some point, I noticed that Percolater was no longer erupting. The quiet continued until the fifth Turban Interval after the Delay, when we got a nice, early fill and a One Burst Grand Eruption. During that eruption, West Triplet finally erupted.

2026-Sep-02 : 18:58:00 D5/G1Q

 18:58:00	B1	--- d=10m38s
 18:58:04	Vent Ovfl	0m04s
 19:08:38	P1	10m38s
 19:09:47	V&T Quit	11m47s

				     	ΣD=10m38s
	* * * * *
 16:24:26			
 16:39:41	Int: 15m15s	d=03m50s	
 16:59:36	Int: 19m55s	d=03m48s	
 17:30:33	Int: 30m57s	d=04m07s D0	
 17:47:03	Int: 16m30s	d=03m44s D1	
 18:05:31	Int: 18m28s	d=03m17s D2	
 18:23:52	Int: 18m21s	d=03m48s D3	
 18:40:40	Int: 16m48s	d=03m37s D4	
 19:04:03	West Triplet
		      Grand: 17m20s

Walking through the Sawmill Group after the Grand eruption, I noticed that Oval Spring was pulsating and rising rapidly. Sawmill was erupting, but Spasmodic was below overflow. I got some video of Oval full with pulsations and waves over the vent, but no bursting. After about a minute, the pool calmed down and then began to drop.


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Observations for 2026 September 01


The wait for the morning Grand wasn't too horrible. The rain had already started as I arrived in time for the Turban eruption prior to the Delay Eruption interval. The rain never got too strong during the next hour.

The rain had mostly ended when the One Burst Grand eruption started explosively, with a wide jet to at least ten meters. It was clear enough that I could see the details of the rest of the start of the eruption. I was able to get back to the cabin without encountering anything more than a slight shower.

2026-Sep-01 : 09:13:13 D3/G1Q

 09:13:13	B1	--- d=10m56s
 09:13:46	Vent Ovfl	0m33s
 09:13:59	Turban	0m46s
 09:16:55	Vent	3m42s
 09:24:09	P1	10m56s
 09:25:09	V&T Quit	11m56s

				     	ΣD=10m56s
	* * * * *
 07:39:59			d=03m30s	
 08:13:04	Int: 33m05s	d=05m04s D0	
 08:30:47	Int: 17m43s	d=04m07s D1	
 08:49:25	Int: 18m38s	d=03m50s D2	
		      Grand: 23m48s

With the rain continuing, it was a good time to be indoors. Finally, it was time to head back out to Grand. About twenty minutes after arrival, West Triplet started to erupt. It ended and Grand had shown no sign of any attempt at erupting, so it was wait for West Triplet to recover.

About an hour later Grand filled slowly and nicely, and we had a long One Burst Grand Eruption. Unfortunately, the overcast kept the eruption from having rainbows.

2026-Sep-01 : 17:21:28 G1Q

 17:21:23	Vent Ovfl	-0m05s
 17:21:26	Boop	-0m02s
 17:21:28	B1	--- d=09m56s
 17:21:32	Turban	0m04s
 17:24:38	Vent	3m10s
 17:31:24	P1	9m56s
 17:32:46	V&T Quit	11m18s

				     	ΣD=09m56s
	* * * * *
 15:24:56			
 15:41:34	Int: 16m38s	d=04m06s	
 15:53:57	West Triplet		d=32m46s
 16:05:45	Int: 24m11s	d=03m39s	
 16:21:57	Int: 16m12s	d=03m38s	
 16:41:39	Int: 19m42s	d=03m57s	
 16:59:49	Int: 18m10s	d=03m30s	
		      Grand: 21m39s

Afterward, I headed to the Bijou Cage for an hour, just to see how things are progressing. If I did not know of the eruption, and had last visited on Saturday, I'd think that not much had changed. During the hour Bijou never stopped, and was on strong. Mastiff was having strong depth charging from the front vent, and I saw two good Mastiff back vent surges. The second one lasted about 20 seconds, and was almost three meters high at one point. The Southwest Vents were making noise, too.


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GeyserExplorer 1.0


I've started work on "GeyserExplorer", a new geyser related app. Unlike GeyserLog (or other GeyserTimes apps), this is not intended as an app for geyser gazers to enter information to the database. Instead, it is an attempt at making that information available in a useful and informative way to visitors to the geyser basins.

Not having to deal with user accounts or data entry makes for a much easier and smaller app, even though I do reuse much from GeyserLog when I can.

The app uses the iPhone GPS/LocationManager to help determine what information to display, based on the user's location. It starts with displaying information only on the main, predicted geysers. The user can change a setting that will include other features, and in the worst case, show every feature in a group or basin. This way a new user is not overwhelmed by useless information on insignificant or dormant features. I'm also looking at ways to filter out geyser-gamer noise.

If anyone is interested in taking a look at this, or testing it, or making suggestions on useful features that should be added, contact me. At some point I can set you up as a beta tester with distribution through the Apple TestFlight app.


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Observations for 2026 August 31


In the morning, did not head out until it was time for Grand. Glad I didn't try for the nighttime eruption, as the interval was about nine hours.

Walked up to the Grand Group with West Triplet full of water and starting to drain. Shortly after was a Turban eruption that was much shorter than typical.

Grand tried to have a Delay on the next Turban eruption interval, and failed. Instead we got 75 seconds of boops, including one that may have been five meters high.

After that, the One Burst Grand was pretty normal, although there was a short false pause at about the time a real pause would have been nice.

2026-Aug-31 : 11:03:07 D0/G1Q

 11:01:52	Boop	-1m15s
 11:03:07	B1	--- d=10m11s
 11:04:21	Turban	1m14s
 11:06:19	Vent	3m12s
 11:11:55	FP	8m48s
 11:13:18	P1	10m11s
 11:15:01	V&T Quit	11m54s
Vent & Turban continue

				     	ΣD=10m11s
	* * * * *
 10:31:53ie	West Triplet
 10:35:39			d=03m11s	
		      Grand: 27m28s

Sawmill was erupting, but Uncertain was pooling on occasion, so stuck around for that. Also got a Castle major eruption while waiting for Uncertain, which seemed to have a shorter duration than previous occasions.

Went on down to the Bijou Cage to see what was happening. Bijou was on strong, but not as high or powerful as it was before the eruption. Catfish was having occasional splashes also. Mastiff was having small surges from the back vent, while there was no depth charging from the front. The Southwest Vents were steaming gently.

A half hour at Fan & Mortar was a place to kill time before going over to see an eruption of Daisy.

West Triplet was erupting as the time of the evening Grand eruption approached. Forty-five minutes later, West Triplet ended just as Rift started to erupt. Except this Rift eruption was weak, and lasted less than 20 minutes. I watched the last minute, and the eruption activity by then consisted of a single vent sputtering to about 25cm, with no overflow.

A half hour later we got the One Burst Grand eruption. The sun had disappeared behind a layer of clouds, and there was only a hint of rainbow in the spray from Vent.

2026-Aug-31 : 18:38:34 G1Q

 18:38:34	B1	--- d=11m00s
 18:39:10	Vent Ovfl	0m36s
 18:39:27	Turban	0m53s
 18:42:23	Vent	3m49s
 18:49:34	P1	11m00s
 18:50:32	V&T Quit	11m58s

				     	ΣD=11m00s
	* * * * *
 17:24:04			d=05m01s	
 17:09:09ie	West Triplet		d>=39m31s
 17:41:25	Int: 17m21s	d=03m38s	
 17:48:25	Rift 			d=19m20s
 18:01:43	Int: 20m18s	d=03m28s	
 18:18:28	Int: 16m45s	d=03m30s	
		      Grand: 20m06s

Also, why is it necessary to add the redundant comment "saw it" to a geyser eruption entry?


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Observations for 2026 August 30


Woke up at about 05:10 by the need to visit the indoor plumbing. Which with our cabin, means a short walk to a different building. It was dark, and it had rained, but the sky seemed mostly clear and the waning moon lit the area up. I got back and checked GeyserTimes for the Grand eruption time, it any. Found it, then noticed the entry above it… The webcam folks had an entry for Giant, almost an hour earlier.

Quickly got myself ready for a nighttime excursion and got on my bike. Arrived at Grotto at 05:45, and could see as I passed by that the Giant platform was steamy with Bijou off. Got over to the Bijou Cage, where Giant was huffing away down deep, and most of the log signs had been moved. There was a slight low tide smell, especially toward the back where grass got flooded. Thanks to the rain, it wasn't possible to tell the extent of any wash zones. Took some video with the powerful flashlight.

Sign locations after Giant Eruption, 2026 August 30.

Hung around the area waiting for it to get light in order to take some video, and to meet others who were headed down basin. Around 07:00, a coyote started barking and howling nearby. I spotted it on the large rock just to the west of Oblong. This behavior continued on for at least a quarter hour, then it move off, probably disturbed by a person walking past Oblong. It continued to make noise, then a second coyote off to the south joined in, and that one headed toward it.

Coyote near Oblong, 2026 August 30.

By 07:30, Grotto was still erupting, and the sky was getting dark and wet.

Spent much of the next hour waiting for the rain showers to lighten up while watching some activity from Spa and Grotto. Then it cleared enough that I was able to make a run for the cabin, and didn't get too wet.

Cold and damp and hungry, and by then it was time for a breakfast at the Lower Store. From there it was out to Grand with the last of the showers. Shortly after, Uncertain had an eruption. During the less than hour long wait, The sky cleared, but it also got a bit windier than it had been during the previous week. It was easy to see the One Burst Grand eruption, which lasted less than nine minutes. Well after that eruption West Triplet finally started.

2026-Aug-30 : 10:54:57 T1C

 10:54:11	Turban	-0m46s
 10:54:57	B1	--- d=08m54s
 10:58:36	Vent	3m39s
 11:03:51	P1	8m54s
Vent & Turban continue

				     	ΣD=08m54s
	* * * * *
 09:56:01			
 10:12:48	Int: 16m47s	d=03m05s	
 10:30:53	Int: 18m05s	d=03m11s	
		     Turban: 23m18s

By the time to go out to Grand again, it was clear, cool, and windy. I dressed warmly, even though the sun was out, as it was getting cloudy in the west, and the wind may not die down after sunset.

Got out in time to see both a Penta steam phase eruption, and the evidence that West Triplet had just ended an eruption. The latter meant there was going to be a bit of a wait for Grand.

As expected, that wait was just under two hours, with no pattern to the intervals between Turban eruptions. When it was finally time for Grand's One Burst Eruption, the pool did fill a bit early, and Vent overflowed for almost half a minute before Grand started.

The wind even died down a bit, which also allowed the tall jets at the start to reach full height. Then there was a gap in the clouds, so the last half of the eruption was nicely illuminated, with Vent contributing a nice rainbow.

2026-Aug-30 : 19:17:09 T1Q

 19:16:43	Vent Ovfl	-0m26s
 19:16:57	Turban	-0m12s
 19:17:06	Boop	-0m03s
 19:17:09	B1	--- d=11m06s
 19:20:05	Vent	2m56s
 19:28:15	P1	11m06s
 19:28:55	V&T Quit	11m46s

				     	ΣD=11m06s
	* * * * *
 17:28:21			d=02m45s	
 17:45:36	Int: 17m15s	d=03m27s	
 18:03:45	Int: 18m09s	d=02m59s	
 18:22:41	Int: 18m56s	d=02m47s	
 18:41:04	Int: 18m23s	d=03m55s	
 19:00:04	Int: 19m00s	d=03m19s	
 19:31:59	West Triplet
		     Turban: 16m53s

Based on past experience, the window for the next Giant eruption, if it is starting a new series, is from five to 21 days. That means we have a few days to do other things before starting to spend too much time in the Bijou Cage. From what we can tell from the leadup to this one eruption, the cessation of Bijou pauses and Mastiff bathtub events is a good sign. This tracks with past experience. Years ago, for example, having a series of regular Hot Period intervals that suddenly got much longer was a sign of possible impending eruption of Giant.

Suzanne stayed out in the Cage until midnight last night, because of the way the platform was behaving. Another observer saw the same minimal pause behavior from Bijou as short as two hours before the eruption. There were also changes in Grotto's behavior in the day or two before Giant erupted, with extremely short durations and intervals.

In this case, the key will probably be the observation of overflow from Mastiff, or erupting activity from the platform from a feature other than the Southwest Vents. Something that breaks up the series of events that all look similar.


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Observations for 2026 August 29


After yesterday evening, I had no desire to go out for the cloudly, wet, moonless eruption of Grand during the night. Instead slept in a bit and then went out to the Bijou Cage to see what might be going on.

It was still gray and overcast, but the rains had quit and weren't supposed to be around for a few hours. Down in the Cage we were getting events every hour or so. What I saw were the minimum, with just Bijou pausing and water just visible in Mastiff, but later there were some with Southwest Vents activity and water visible in Feather. But what I did see were Bijou pauses that lasted well over four minutes, with the water in Mastiff only becoming visible midway through the pause.

After several hours, the weather got nicer, with some actual breaks in the clouds and sun warming things up. Transfered my attentions down to Grand, where once again it was over two hours of Turban intervals that slowly got shorter, down to about 16 minutes.

Then West Triplet started, and the One Burst Grand eruption started on the first opportunity ten minutes later. This eruption was notable in that there was a relatively long False Pause, a little over eight minutes into the eruption, that lasted about three seconds, long enough to note the end of the time. It felt like the pool was quiet, but a review of the video shows several boop-like boils during that short period.

2026-Aug-29 : 13:05:39 T1C

 13:05:17	Vent Ovfl	-0m22s
 13:05:20	Turban	-0m19s
 13:05:30	Boop	-0m09s
 13:05:39	B1	--- d=09m44s
 13:08:37	Vent	2m58s
 13:13:53	FP	8m14s
 13:15:23	P1	9m44s
Vent & Turban continue

				     	ΣD=09m44s
	* * * * *
 10:43:54			d=03m38s	
 11:02:35	Int: 18m41s	d=03m18s	
 11:21:06	Int: 18m31s	d=03m24s	
 11:39:43	Int: 18m37s	d=03m46s	
 11:58:14	Int: 18m31s	d=03m36s	
 12:14:30	Int: 16m16s	d=02m51s	
 12:31:22	Int: 16m52s	d=03m06s	
 12:47:23	Int: 16m01s	d=03m19s	
 12:55:48	West Triplet
		     Turban: 17m57s
Grand False Pause, 2026 August 29 13:05

Afterwards, the pouring rain waited until I was inside the cabin.

Waited several hours for the rain showers to stop, then headed back out to the Bijou Cage. Oblong started to erupt just as I rode past. Over at the cage, nothing much happened while I was there, then it was time to head back to Grand.

Walking through the Sawmill Group, I noticed that Churn was almost at overflow. Slurp was liquid with the usual steamy noise. Belgian Pool was high, with the side lobe full and a bit murky. In the past it seems that murkiness happens after heavy rains.

It was then I realized that I was an hour earlier than I needed to be. Instead of leaving, I just waited things out. As it was, the next Turban eruption became a Turban Delay Interval. After four more Turban eruptions, West Triplet finally started.

The One Burst Eruption took place on the second Turban eruption after West Triplet had started. As I had expected earlier, this eruption took place in that gap between sunset and moonrise, so it was pretty dark.

2026-Aug-29 : 20:59:47 D6/T1C

 20:59:45	Turban	-0m02s
 20:59:47	B1	--- d=09m50s
 21:09:37	P1	9m50s
Vent & Turban continue

				     	ΣD=09m50s
	* * * * *
 18:38:54			d=03m52s	
 19:12:41	Int: 33m47s	d=05m27s D0	
 19:30:30	Int: 17m49s	d=03m55s D1	
 19:49:30	Int: 19m00s	d=03m46s D2	
 20:08:28	Int: 18m58s	d=04m12s D3	
 20:26:26	Int: 17m58s	d=03m28s D4	
 20:31:59	West Triplet
 20:42:29	Int: 16m03s	d=03m15s D5	
		     Turban: 17m16s

Afterwards I went back to the Bijou Cage for a while, as there hadn't been any Bijou pauses or Mastiff bathtubs for several hours. By then the moon was well above the ridge, and the clouds had cleared away. Two hours later I left with no change in the activity.


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Observations for 2026 August 28


It rained during the night, but at dawn it was just gray and damp. I arrived at the Grand Group to see that West Triplet and its runoff channel were empty but steaming. So ended up waiting in the rain for the next West Triplet eruption. It only started to sprinkle near the end of the wait for another One Burst Eruption from Grand. Another eruption just long enough, while too long for a first burst, it appears.

2026-Aug-28 : 08:51:03 G1C

 08:51:00	Boop	-0m03s
 08:51:03	B1	--- d=09m33s
 08:51:06	Vent Ovfl	0m03s
 08:51:26	Turban	0m23s
 08:54:09	Vent	3m06s
 09:00:36	P1	9m33s
Vent & Turban continue

				     	ΣD=09m33s
	* * * * *
 06:42:03			d=03m52s	
 07:01:28	Int: 19m25s	d=04m01s	
 07:20:29	Int: 19m01s	d=03m53s	
 07:39:37	Int: 19m08s	d=03m55s	
 07:58:48	Int: 19m11s	d=03m43s	
 08:18:03	Int: 19m15s	d=03m36s	
 08:34:11	Int: 16m08s	d=03m31s	
 08:50:53	West Triplet
		      Grand: 16m52s

The Boardwalk Crew had arrived and were setting up by Castle. I overheard them say they were closing the boardwalk around the Sawmill junction. I did ask if the walkway would be open, and was told they'd be done around 15:00.

It does seem that too often at the start of Grand's eruption there can be light or no rain, but by the time I get back to the cabin, it's pouring and I'm soaked.

The rains had mostly ended by the next time to head out to Grand. The Boardwalk Crew removed their barricades just after 15:00. It was a bit early but I wanted to beat the shower that the weather map showed was headed our way. As it turned out, it never got here.

That began a four hour wait of a long series of Turban eruptions where the intervals slowly got shorter until West Triplet erupted. During that time we got to see another eruption of Oblong, as well as another Castle major eruption. When Turban erupted after the end of the West Triplet eruption and Grand didn't erupt, I knew that we had well over an hour of waiting ahead of us.

Finally we got a good, early fill and Grand started right after Turban with several tall spikes in the starting activity. When the first burst ended at about 9-1/2 minutes, I expected that to be the eruption. Instead, a quick 20 seconds later we got another burst. This one wasn't as tall and came within two seconds of being a Long Second Burst.

2026-Aug-28 : 19:15:51 T2Q

 19:15:40	Turban	-0m11s
 19:15:45	Vent Ovfl	-0m06s
 19:15:47	Boop	-0m04s
 19:15:51	B1	--- d=09m27s
 19:18:25	Vent	2m34s
 19:25:18	P1	9m27s d=20s
 19:25:38	B2	9m47s d=01m13s
 19:26:51	P2	11m00s
 19:27:56	V&T Quit	12m05s

				     ΣB=10m40s	ΣD=11m00s
	* * * * *
 15:08:59			
 15:24:50	Int: 15m51s	d=04m03s	
 15:44:21	Int: 19m31s	d=04m01s	
 16:03:57	Int: 19m36s	d=03m34s	
 16:21:44	Int: 17m47s	d=03m30s	
 16:39:42	Int: 17m58s	d=03m42s	
 16:56:38	Int: 16m56s	d=03m23s	
 17:13:24	Int: 16m46s	d=03m12s	
 17:19:29	West Triplet d=39m21s
 17:31:10	Int: 17m46s	d=03m29s	
 17:48:03	Int: 16m53s	d=03m20s	
 18:04:37	Int: 16m34s	d=03m06s	
 18:25:05	Int: 20m28s	d=04m04s	
 18:42:34	Int: 17m29s	d=03m35s	
 18:59:16	Int: 16m42s	d=03m25s	
		     Turban: 16m24s

I do wonder why there are three webcam reports of Beehive erupting this morning when there was already a report from an observer in the basin. Gotta get those geyser gamer points any way you can, I guess.


Posted on

Observations for 2026 August 27


Once again, headed out to Grand at dawn. Did see post-eruption steaming in Uncertain as I went past. I had to wait 18 minutes from my arrival to see the first Turban eruption, and based on the lack of overflow on the next Turban eruption, I would say I got to see a Turban Delay Interval.

A half hour later, Castle could be heard erupting. It was clear when I crossed over, but by then it was foggy enough that only the top of Castle's steam column was visible. It was a major eruption, and the sound of the steam was loud since there wasn't any background noise from the road and all the other activities of the day.

Grand finally erupted on the fifth Turban eruption after the Delay, and it was a steamy, but backlit One Burst Eruption. West Triplet started midway through the eruption.

2026-Aug-27 : 08:10:37 T1Q

 08:10:21	Turban	-0m16s
 08:10:23	Vent Ovfl	-0m14s
 08:10:34	Boop	-0m03s
 08:10:37	B1	--- d=10m05s
 08:13:20	Vent	2m43s
 08:20:42	P1	10m05s
 08:23:02	V&T Quit	12m25s
Vent & Turban continue

				     	ΣD=10m05s
	* * * * *
 06:40:18			d=04m35s	
 06:57:15	Int: 16m57s	d=03m51s	
 07:17:47	Int: 20m32s	d=03m48s	
 07:36:04	Int: 18m17s	d=03m24s	
 07:51:45	Int: 15m41s	d=03m14s	
 08:16:47	West Triplet
		     Turban: 18m36s

Then it was down to the Bijou Cage. Other than Bijou erupting away, nothing happened there for an hour. Then we got a strong Mastiff surge. Within a minute water was visible in Mastiff. Bjiou did not shut down, and barely slowed down. There was some spitting from the Southwest Vents, and thanks to the sun angle, water could easily be briefly seen in Feather. After Mastiff dropped, Catfish and the B-C Vent splashed briefly, and Bijou began roaring.

On the way back from the Cage, I was leisurely riding my bike down from Castle when Tara Cross came racing past me on her bike. I realized that I had turned off my radio during the bathtub event, and looking over at Geyser Hill, could see the steam from the Indicator. I picked up speed and followed her and was able to get to Geyser Hill in plenty of time to see the Beehive eruption. Once again, the little opening at the bottom of Beehive's cone was spitting water about 10-15cm from the cone during the time when Beehive's Indicator was erupting.

I went back out to Grand in the afternoon. Over a 2-1/2 hour period, I got to see nine eruptions of Turban where the intervals and durations got progressively shorter. After a 15-1/2 minute interval, there was a longer twenty minute duration, where Grand looked like it could erupt-- the pool was full and having small waves. But it dropped as Turban started. Twenty minutes later, West Triplet finally started erupting, and Grand took the next opportunity to also erupt.

The One Burst Eruption lasted well under ten minutes, but once the burst ended, Grand refilled, and for almost 1-1/2 minutes, water sloshed around the pool as if we might get a second burst. Then Grand drained, and Vent & Turban also quit.

2026-Aug-27 : 17:15:41 G1Q

 17:15:41	B1	--- d=09m40s
 17:15:46	Turban	0m05s
 17:18:21	Vent	2m40s
 17:25:21	P1	9m40s
 17:26:44	Drain	11m03s
 17:27:07	V&T Quit	11m26s

				     	ΣD=09m40s
	* * * * *
 14:33:09			d=03m29s	
 14:51:27	Int: 18m18s	d=03m10s	
 15:12:28	Int: 21m01s	d=03m33s	
 15:31:33	Int: 19m05s	d=03m32s	
 15:50:20	Int: 18m47s	d=03m47s	
 16:08:38	Int: 18m18s	d=03m33s	
 16:23:58	Int: 15m20s	d=02m55s	
 16:43:58	Int: 20m00s	d=03m05s	
 16:59:36	Int: 15m38s	d=03m29s	
 17:05:17	West Triplet
		      Grand: 16m05s

Forty-five minutes after the start of the West Triplet eruption, Rift also began erupting.

The little bit of shade where the walkway narrows in front of Rift always attracts people who clog up the walkway. Today they brought folding chairs (and also were off trail in the trees) and forced everyone as tall as I am to have to duck under the branches of the tree.

Boardwalk blockers at Rift

The partial lunar eclipse was a bust. At first there were clouds with lightning to the southeast, blocking the view. Then it rained.

When I headed out to Grand, the eclipse had passed the mid-point. The clouds were thinning out, so it was hard to tell that the moon wasn't completely full. Out at Grand, it appeared that Turban was about to have a Delay Interval, when instead Turban started to erupt. The steam from Grand's pool didn't look like it was building to an eruption, so it was a pleasant surprise when it started.

As with the afternoon eruption, the duration was less than ten minutes, and after a bit of a delay, Vent & Turban quit. I suspect that during those two minutes Grand was attempting to have a second burst, and failed.

2026-Aug-27 : 23:52:03 T1Q

 23:51:19	Turban	-0m44s
 23:52:03	B1	--- d=09m39s
 00:01:42	P1	9m39s
 00:03:35	V&T Quit	11m32s

				ΣD=09m39s
	* * * * *
 23:27:09			d=04m09s	
		     Turban: 24m10s

As we left, realized it had been 17 hours since Castle erupted. So waited a while, but Castle wasn't even sloshing. I decided to head in, and before I could put on my pack, the eruption started. For the first few minutes, Castle acted as if it was going to have a minor eruption, but after the seven minute mark, there was little doubt that it would be a major eruption.

By this time, the clouds were all gone and the eclipse over. There was also a moonbow visible low in the steam and spray wetting down the boardwalk.


Posted on

Observations for 2026 August 26


Got up before dawn and headed out to Grand at the 7-1/2 mark. Arrived there and the pool was full. Castle had a major eruption that started around that same time.

The wait for Grand was nearly 2-1/2 hours, a series of unremarkable Turban eruptions, although during that time we did get to see an eruption of Oblong. The One Burst Grand eruption was long, nearly 12-1/2 minutes long.

2026-Aug-26 : 08:19:05 T1Q

 08:18:29	Turban	-0m36s
 08:18:48	Vent Ovfl	-0m17s
 08:18:55	Boop	-0m10s
 08:19:05	B1	--- d=12m41s
 08:21:27	Vent	2m22s
 08:31:47	P1	12m41s
 08:32:31	V&T Quit	13m25s

				     	ΣD=12m41s
	* * * * *
 05:53:05			d=03m44s	
 06:11:23	Int: 18m18s	d=03m46s	
 06:30:53	Int: 19m30s	d=03m53s	
 06:50:12	Int: 19m19s	d=03m33s	
 07:07:53	Int: 17m41s	d=03m17s	
 07:25:15	Int: 17m22s	d=03m12s	
 07:30:18	West Triplet d=36m03s
 07:43:06	Int: 17m51s	d=03m00s	
 07:58:16	Int: 15m10s	d=03m10s	
		     Turban: 20m13s

While waiting, we had two bison appear down by Beauty Pool and slowly head our way. One went in back of Turban and Grand in the steam, while the other headed directly for the benches. As expected, it just passed by, and both disappeared up the hillside behind Rift. (I wanted to post a picture, but it was so close that the camera only captured its top half.)

Had originally intended to head down the Giant after Grand, but the wait was so long we decided to head in and reconfigure first. Then it was down to the Bijou Cage.

In the two hour wait, at first there were a couple of small Mastiff far vent surges, then nothing happened for over an hour. We finally got a large surge, followed by water in Mastiff, but Bijou didn't even slow down much. When Mastiff refilled, Catfish and the B-C vent erupted for a few seconds, the Bijou began roaring for about 1/2 minute.

After lunch in the cabin, returned to the Cage for an hour, where I got to see the Oblong eruption, the fourth in two days.

From there, it was back to the Grand Group, where Turban had a long series of eruptions. West Triplet started about 45 minutes after arrival, the another 45 minutes later, Rift started. That eruption lasted about 40 minutes, and then we had the One Burst Eruption on the next opportunity.

2026-Aug-26 : 16:49:17 T1C

 16:49:03	Vent Ovfl	-0m14s
 16:49:09	Boop	-0m08s
 16:49:15	Turban	-0m02s
 16:49:17	B1	--- d=09m52s
 16:52:10	Vent	2m52s
 16:59:10	P1	9m52s
Vent & Turban continue

				     	ΣD=09m52s
	* * * * *
 14:43:06			d=04m10s	
 15:02:18	Int: 19m12s	d=03m58s	
 15:13:36ns	West Triplet d=01h05m
 15:20:56	Int: 18m38s	d=03m45s	
 15:38:32	Int: 17m36s	d=03m47s	
 15:56:38	Int: 18m05s	d=03m35s
 15:58:54	Rift
 16:15:52	Int: 19m14s	d=04m08s	
 16:33:13	Int: 17m20s	d=02m49s	
		     Turban: 16m01s

The day before the full moon, so it was bright out, along with partly cloudy. Walked up to West Triplet in eruption, and had just enough time to settle in when Turban had one of its explosive starts, followed by Grand.

A strong breeze kicked up, pushing the steam out so that there really wasn't a good place on any part of the boardwalk to see the One Burst Grand for much of the time. And having the moon disappear behind a cloud didn't help. But was nice that we had no wait.

2026-Aug-26 : 23:30:16 T1C

 23:30:02	Turban	-0m14s
 23:30:16	B1	--- d=09m21s
 23:33:17	Vent	3m01s
 23:39:37	P1	9m21s
Vent & Turban continue

				     	ΣD=09m21s
	* * * * *
 23:25:25ie	West Triplet

Posted on

Observations for 2026 August 25


It was dawn and I was walking down from Crested Pool when I saw what appeared to be an eagle flying low upstream along the Firehole River. When I got to the bridge, that's when Grand began to erupt.

Took a little longer to get over there, because the boardwalk between Sawmill and Belgian is in the hands of the trail crew. But arrived in plenty of time to catch the end of the first burst, which lasted just under nine minutes. After a fairly normal pause, I got well over two more minutes of activity.

2026-Aug-25 : 06:27:44 2*Q

 06:27:44	B1	--- d=08m50s
 06:36:34	P1	8m50s d=42s
 06:37:16	B2	9m32s d=02m21s
 06:39:37	P2	11m53s
 06:40:17	V&T Quit	12m33s

				     ΣB=11m11s	ΣD=11m53s

Since I was already up and around and prepared to be out for a while, there was no reason to head back in. Instead I went down to the Bijou Cage. The Giant platform looked like nothing much had happened recently. The area around the Southwest Vents was dry, and the small puddles in front of Giant looked like they came from its activity. There was a bit of water in the far runoff coming from Mastiff, but it was a cool, damp night.

Was there for nearly two hours, and saw a few small Mastiff surges, but the last one was almost an hour before I left. At that point, I went in for breakfast, and returned to the cage about an hour later.

This time I had barely settled in when Mastiff had a huge surge to at least two meters that lasted 45 seconds. Sometimes Bijou pauses after these surges, so I kept watching, and while Bijou did not stop, water became visible in Mastiff.

Water was not high, maybe down 30cm, and was only visible for less than 1-1/2 minutes. I saw one spit from the Southwest Vents. By the end, Bijou, which had never stopped, was erupting even stronger. It then began roaring with Catfish active.

Left the cage and the basin for a while, and about 1/2 hour later, Oblong erupted for the first time in several months. Returned to the cage briefly, just to confirm that nothing major had happened at Giant during Oblong's eruption.

Then headed over to Grand just in time for the Turban Delay Interval eruption. Was pleasantly surprised that we only had to wait four Turban eruption intervals before the One Burst Grand. The eruption started in shadow, but the cloud moved away by the start of Vent. Shortly after that, West Triplet also erupted.

2026-Aug-25 : 14:20:24 D4/G1Q

 14:20:16	Vent Ovfl	-0m08s
 14:20:21	Boop	-0m03s
 14:20:24	B1	--- d=10m12s
 14:20:27	Turban	0m03s
 14:23:28	Vent	3m04s
 14:30:36	P1	10m12s
 14:32:43	V&T Quit	12m19s

				     	ΣD=10m12s
	* * * * *
 13:02:49			d=04m38s D0	
 13:19:38	Int: 16m49s	d=04m15s D1	
 13:39:07	Int: 19m29s	d=03m54s D2	
 13:59:00	Int: 19m53s	d=03m50s D3	
 14:25:56	West Triplet
		      Grand: 21m24s

As we left Grand, we got to see the second Oblong eruption of the day. Thanks to the trail construction, we didn't try to backtrack to see it from the Grand benches.

From there, it was back to the Bijou Cage again. A half hour after my arrival, I got another large Mastiff surge (ten minutes after the previous, smaller surge). Two minutes later Bijou was off. Water never rose very high in Mastiff, and again there was only a splash or two from the Southwest Vents. The pause lasted 3-1/2 minutes, and once again, when Bijou started, it began to roar. Catfish and the C-B Vent also showed some activity at that time.

Went back out again in the late evening, after getting some overhead done back in the cabin and after waiting for a shower to pass. Waited almost an hour before finally got a large Mastiff surge that led to a Bijou pause. It was similar to all the previous pauses, with Mastiff showing visible water and a couple of Southwest Vent splashes. The pause lasted almost four minutes, and then began roaring after the restart. Grotto was erupting as I left, but I didn't notice the start.

West Triplet was in eruption as we arrived for the evening moonlight Grand eruption. Shortly after West Triplet ended Percolator also paused for about 1-1/2 minutes. It was disconcerting for there to be silence out there.

There was little runoff prior to the Grand eruption start. The start itself was sudden and explosive. By a nearly full moon, the second burst seemed to be tall and thin.

2026-Aug-25 : 22:03:54 D0/G2Q

 22:03:54	B1	--- d=09m14s
 22:13:08	P1	9m14s d=23s
 22:13:31	B2	9m37s d=40s
 22:14:11	P2	10m17s
 22:15:01	V&T Quit	11m07s

				     ΣB=09m54s	ΣD=10m17s
	* * * * *
 20:56:31ie	West Triplet
 20:57:49			d=03m39s	
 21:17:56	Int: 20m07s	d=03m39s	
 21:37:29	Int: 19m33s	d=04m02s	
		      Grand: 26m25s

And this evening I learned that Ernesto has left the basin.


Posted on

Observations for 2026 August 24


Based on the recent short intervals, headed back out to Grand before the seven hour mark, while it was still dark. Ended up waiting six Turban eruption intervals. For most of the wait the breeze was non-existent, but during the eruption the benches on the north end got soaked, and I'm sure there's not much to see on the video

2026-Aug-24 : 07:48:08 G2Q

 07:48:06	Boop	-0m02s
 07:48:08	B1	--- d=09m15s
 07:48:57	Turban	0m49s
 07:51:34	Vent	3m26s
 07:57:23	P1	9m15s d=40s
 07:58:03	B2	9m55s d=44s
 07:58:47	P2	10m39s
 07:59:30	V&T Quit	11m22s
 08:09:35	V&T Restart	21m27s

				     ΣB=09m59s	ΣD=10m39s
	* * * * *
 06:01:20			d=04m47s	
 06:18:36	Int: 17m16s	d=03m48s	
 06:37:02	Int: 18m26s	d=03m48s	
 06:54:49	Int: 17m47s	d=03m34s	
 07:13:27	Int: 18m38s	d=03m07s	
 07:28:56	Int: 15m29s	d=03m20s	
		      Grand: 19m12s

Afterwards, decided another wait in the Bijou Monkey Cage was in order. One bit of Guru Geyser Gazing I've noticed is that the events of the last few days have come on six hour (or multiple of six hour) intervals. The meant that we had a chance for something to happen around noon.

After a two hour wait with only small Mastiff far vent surges every 10 or 20 minutes or so, we got a large surge. Bijou was already completely off at that point. Shortly after, water was visible rising in Mastiff. At first there were a few spits from the Southwest Vents, and some splashes from Catfish. A minute later the Southwest Vents were putting out a couple of streams of runoff. We also noticed that water appeared to be pooling in Feather, but it was hard to be certain.

Bijou came back on after a pause of at least 4m17s. Catfish also had some tall surges, and the "C-B Vent" erupted briefly to about 20cm.

Before the event started, there were a group of four men talking at the other end of the platform, and it sounded like they had some knowledge of geysers and the Giant area. Just before the event started, it looked like they had started an on camera interview. So in the background of their video they have Suzanne and I suddenly climbing the bench and staring at the platform, with Suzanne making announcements over the radio for the duration.

They may have been doing a video for the YVO or some such. In any case, I'd definitely be interested in hearing if anyone sees such a video.

During that wait, I also heard a woman in a family group ask, "Which one's Giant?"

Got back to the cabin (after a forced NPS bison babysitting detour) and shortly after got the Beehive radio call. During the eruption I noticed a small vent squirting water out to the north from a hole about 15cm above the platform to a distance of about 1/4 meter. It quit with Beehive's Indicator. It was windy, so the eruption of Beehive got the usual stretch of boardwalk wet.

West Triplet started erupting just as I tied my bike down at Castle. With no following eruption of Rift, I expected a wait of a few hours until the next West Triplet eruption window. Two and a half hours later, Grand filled nicely, followed by almost 15 seconds of boops before the One Burst Eruption started. Midway through that, West Triplet started erupting.

2026-Aug-24 : 16:33:13 G1Q

 16:32:58	Boop	-0m14s
 16:33:13	B1	--- d=11m03s
 16:33:36	Vent Ovfl	0m23s
 16:34:02	Turban	0m49s
 16:36:07	Vent	2m53s
 16:44:16	P1	11m03s
 16:45:05	V&T Quit	11m52s

				     	ΣD=11m03s
	* * * * *
 13:59:31ie	West Triplet d=35m33s
 14:18:05			d=04m13s	
 14:37:08	Int: 19m03s	d=03m40s	
 14:57:02	Int: 19m54s	d=04m04s	
 15:16:25	Int: 19m23s	d=03m39s	
 15:35:47	Int: 19m22s	d=03m24s
 15:52:35	Int: 16m48s	d=03m42s
 16:11:09	Int: 18m33s	d=03m23s
 16:40:41	West Triplet
		      Grand: 22m03s

Since it was nearly six hours since we saw the Mastiff bathtub hot period, we went down to the Bijou Cage to wait and see if the six hour intervals would hold. Ten minutes after arriving, we got a huge surge from Mastiff, which lead off a shorter and weaker bathtub. While the water level in Mastiff seemed the same, there wasn't any Southwest Vents activity other than a few spits, and the Bijou pause was shorter. The next two opportunities are going to be in the dark, and we won't be attending.


Posted on

Observations for 2026 August 23


Since the thunderstorms last night kept me from going out and seeing Grand, I went out at dawn not knowing what to expect. (Dawn is now after 06:00 and getting later every day.)

It was cloudy with fog down below. I got out to find Grand in heavy overflow that ended almost immediately, followed by Turban erupting. The next Turban interval had no overflow, and the next was a long Delay Interval.

After that, it was an uneventful wait until Grand filled nicely for the fourth Turban eruption. The One Burst Grand was a steamy mess, with a wind blowing steam and spray all over the northern benches.

2026-Aug-23 : 08:36:24 D4/G1Q

 08:36:22	Boop	-0m02s
 08:36:24	B1	--- d=10m35s
 08:37:27	Turban	1m02s
 08:40:08	Vent	3m43s
 08:47:00	P1	10m35s
 08:48:17	V&T Quit	11m52s

				     	ΣD=10m35s
	* * * * *
 06:24:52			d=04m55s
 06:43:45	Int: 18m53s	d=04m11s	
 07:16:58	Int: 33m12s	d=05m14s D0	
 07:35:34	Int: 18m35s	d=04m03s D1	
 07:55:46	Int: 20m12s	d=03m56s D2
 08:16:45	Int: 20m58s	d=03m47s D3
		      Grand: 19m38s

Next it was down to the Bijou Monkey Cage. Over the a period of over two hours we saw a few Mastiff surges, but Bijou never paused. then there was a surge that, unlike the previous surges, started slowly instead of suddenly. That built into a the largest surge of the morning, and about then Bijou slowed and paused.

The pause lasted 3m09s. The water in Mastiff was at about the same level as yesterday. There were a couple of spits from the Southwest Vents, but no large surging in Giant.

I got the Beehive Indicator call in the cabin, and made it to the railing for the start of Beehive's eruption. It was windy, and no way I was going to proceed further.

An hour later it was time to return to Grand. West Triplet was in eruption as I tied down my bike. We only had to wait one Turban eruption interval, and the Grand start was a bit of a surprise. It also took Vent about 4-1/2 minutes to start. West Triplet ended early in the Grand eruption.

2026-Aug-23 : 15:30:48 G1C

 15:30:48	B1	--- d=09m22s
 15:31:23	Turban	0m34s
 15:35:15	Vent	4m26s
 15:40:10	P1	9m22s
Vent & Turban continue

				     	ΣD=09m22s
	* * * * *
 15:01:09ie	West Triplet
 15:08:24			d=04m10s	
		      Grand: 22m24s

With the short wait, it was on to the Bijou Cage. After about a two hour wait with a few small Mastiff surges, we finally got a Bijou pause. This was similar to the activity we'd seen this morning, except this time the Southwest Vents were active during the last minute, putting out enough water to form pools on both the platform and the shelf below.

Overflow from Southwest Vents during Mastiff bathtub. 2026 Aug 23 18:06

Finally went out for a nighttime Grand. It was mostly clear, and the gibbous moon was bright enough. Had to wait just over an hour, with no Turban Delay intervals, and finally got to see a two burst eruption. In the middle of the first burst, the moon disappeared behind a cloud, so the second burst was just barely visible. The total eruption lasted less than ten minutes, and then Vent & Turban quit.

2026-Aug-23 : 23:04:40 T2Q

 23:04:20	Turban	-0m20s
 23:04:40	B1	--- d=08m19s
 23:12:59	P1	8m19s d=42s
 23:13:41	B2	9m01s d=49s
 23:14:30	P2	9m50s
 23:15:30	V&T Quit	10m50s

				     ΣB=09m08s	ΣD=09m50s
	* * * * *
 21:52:10			d=04m01s	
 22:10:27	Int: 18m17s	d=03m45s	
 22:29:10	Int: 18m43s	d=03m15s	
 22:44:52	Int: 15m42s	d=03m38s	
		     Turban: 19m28s

Posted on

Observations for 2026 August 22


As expected, Grand was below overflow, and I estimated that the eruption had happened about three hours earlier. So plenty of time to go down to Giant and see what happened.

I arrived there and Bijou was on strong, with no evidence of any recent platform activity. Across the river the steam rising from the Purple Pools runoff channel was obvious.

Every so often Mastiff would have a strong surge with thick jetting to the south, refreshing the shallow puddle between it and the base of Giant's cone. In a couple of cases, these surges preceded a Bijou pause or slowdown.

After 2-1/2 hours, I left to go and get ready for the next Grand eruption. Instead as I arrived at the cabin, I heard the radio call for the One Burst Eruption.

So I went back out to Giant. I was gone for about 50 minutes. As I arrived, I noticed that the Giant Indicator Pool (GIP) was high, about 30cm below the rim. Normally I can't see the water level. I was told that Bijou had not pause while I was gone, so it had been active for about two hours.

Mastiff continued to have some surges, some fairly large. Giant was also having surges that reached above the top of the bite in on the right side of the cone. These large surges would put water out the front of Giant, refreshing the puddle there.

Catfish was mostly quiet, but once I did see some splashing from it for a few seconds.

Finally, over six hours since the last pause, Rocket had a major eruption about 2-1/2 hours into a Grotto eruption. Then there was perhaps the largest Mastiff surge seen yet, and shortly after, Bijou quickly got quiet. Forty five seconds later water was visible in Mastiff. It never got higher than 30cm below the rim. The Southwest Vents did splash for a few seconds, and Giant had one large surge to the top of the cone. After 3-1/2 minutes, Bijou restarted.

Mastiff surge prior to Mastiff bathtub, 2026 Aug 22 14:45
Giant surge during Mastiff bathtub, 2026 Aug 22 14:45

Grotto finished erupting shortly after, for a duration of just under three hours. Water was not visible in the GIP.

Once again returned to the cabin to get ready for Grand. Because of the previous short interval, I decided to get out early. As it was, I saw Rift erupting when I arrived at the bike rack, but it had finished by the time I got over there. Turban started erupting as I sat down on the bench, and as I pulled my camera tripod out of the pack, Grand followed with another One Burst Eruption, one lasting 9m21s.

2026-Aug-22 : 16:04:50 T1C

 16:04:27	Turban	-0m22s
 16:04:50	B1	--- d=09m23s
 16:07:37	Vent	2m46s
 16:14:14	P1	9m23s
Vent & Turban continue

				     	ΣD=09m23s

While I was out in the Bijou Monkey Cage, a geyser gamer reported an eruption of Daisy over the radio. I look over and see no steam, so figure either he's wrong, or he was reporting the very end of an eruption. I wait and look over frequently, and ten minutes later, I see Daisy start. So I make a post for the real eruption, then flag the erroneous report. First that report gets change to have the proper near start time. Then it gets deleted, along with my flag, and a new, superfluous secondary posting with a near star time appears. Why this person felt the need to duplicate my posting after screwing up, I don't know.


Posted on

Observations for 2026 August 21


The radio call for a Penta major eruption went out just as we were about to head out into the basin. There was no report on Grand, and it had been only 14 hours since the previous observation. We also had to vacate our cabin so we could transfer later in the day to the one we prefer.

Got out to Penta and it was definitely in a major eruption. The start, however, was different from years ago in that Penta started without any overflow. Since Sawmill doesn't overflow before erupting any more, that makes sense. It lasted about 1-1/2 hours, and during most of that time Penta's Sixth Vent had a pool of water with bubbling in the middle. It may be time for the squirrels to clean it back out.

Water levels stayed high in the Sawmill Group for about an hour, then first Spasmodic, then Sawmill started to drop. The end of the Penta eruption took about a minute to go from full height to quiet. Then, about two minutes later, splashing started first in the Top vent, then in the Bottom vents.

Over at Grand, Sput C1 and the area behind the flat rock next to the runoff channel were steaming (Sput E1?). Belgian Pool had a water level where it was just starting to get wet in the side lobe.

I left the Penta splashing and got over to Grand just in time for the start of a One Burst Eruption. This One Burst Grand not only lasted only 9m39s, but Vent & Turban quit. What should have been a long first burst turned into a short eruption.

2026-Aug-21 : 08:43:42 T1Q

 08:42:57	Turban	-0m45s
 08:43:42	B1	--- d=09m39s
 08:46:20	Vent	2m38s
 08:53:21	P1	9m39s
 08:54:56	V&T Quit	11m14s
 09:02:24	V&T Restart	18m42s

				     	ΣD=09m39s
	* * * * *
 07:26:52			d=04m06s	
 07:48:35	Int: 21m43s	d=03m48s	
 08:08:20	Int: 19m45s	d=03m44s	
 08:26:24	Int: 18m04s	d=03m09s	
		     Turban: 16m33s

Right after Grand ended, West Triplet started. I didn't stick around to wait for Rift.

I noticed that at Crested Pool there was water pooling between the outer formations and the walkway, as if Crested is pushing out more water, or has a bit higher water level.

After a breakfast, it was time to kill time on Geyser Hill. Saw a Lion series initial eruption from the benches by Beehive, then Beehive itself. Despite being after noon, there as no wind so Beehive was tall accessible from the railings.

We finally got moved in and after a much needed rest, it was time for Grand.

Based on recent activity, it looks like there's not much reason to be out at Grand before seven hours. But I got out a bit early as I wasn't sure how crowded things might get with the wide NPS window starting around 6-1/2 hours. As it turned out, I was pretty much alone on the benches for the first few Turban eruptions.

The wait consisted of a couple of hours of slowly shortening Turban intervals. Then on a 16 minute interval, we got Vent overflowing along with a vigorous Turban eruption. That eruption was short, and followed by a Turban eruption interval with no overflow.

Before the Vent Delay Turban eruption, West Triplet finally started. With that delay, I figured we had a chance on the second Turban eruption after the Delay eruption. By then West Triplet had erupted long enough to either end, or have Rift start. Rift was steaming heavily when I noticed that Grand was having another early fill and looking good. Rift finally started at the same time Turban started erupting. Vent overflowed at the same time, and for the next minute the waves on Grand got heavier. Finally we got a good sized boop and the start of Grand.

The One Burst Eruption was quite tall, with a noticeable base surge cloud rolling over the runoff channels. Before Vent started erupting, I noticed that West Triplet was no longer erupting. That was followed by Rift quitting during Grand, for a duration of about nine minutes.
Vent & Turban quit again, and restarted about seven minutes later.

2026-Aug-21 : 18:31:17 V3/T1Q

 18:30:48	Vent Ovfl	-0m29s
 18:30:51	Turban	-0m26s
 18:31:11	Boop	-0m06s
 18:31:17	B1	--- d=10m45s
 18:33:39	Vent	2m22s
 18:42:02	P1	10m45s
 18:42:49	V&T Quit	11m32s
 18:49:38	V&T Restart	18m21s

				     	ΣD=10m45s
	* * * * *
 15:30:32			d=03m45s	
 15:52:28	Int: 21m56s	d=03m49s	
 16:11:29	Int: 19m01s	d=03m46s	
 16:30:08	Int: 18m39s	d=03m34s	
 16:49:04	Int: 18m56s	d=03m32s	
 17:06:40	Int: 17m36s	d=03m14s	
 17:23:22	Int: 16m42s	d=03m22s	
 17:39:38	Int: 16m16s	d=03m17s V0 Vent ovfl: 17:39:41	
 17:43:36	West Triplet
 17:56:44	Int: 17m06s	d=02m53s V1	
 18:13:47	Int: 17m03s	d=03m55s V2	
 18:29:58	Rift
		     Turban: 17m04s

I also learned that there must not be any geyser gamer point penalties for leaving a One Burst Grand Eruption once it becomes obvious that there will not be a subsequent burst.


Posted on

Observations for 2026 August 20


Of course Grand erupted as we were in the Lodge checking in. As it was, an eight Turban Interval delay before the One Burst Eruption meant we didn't miss much.

Instead decided to go take a look at Giant. Spent about 1-1/4 hour in the Bijou Cage. During that time there was only one time that Bijou was not jetting strongly. For about three minutes it was almost off, with an occasional splash every few seconds.

Shortly after we arrived, Mastiff has a voluminous surge out of the back/south vent. This reached a height of about 2 meters, and lasted about ten seconds. It looked like how I remember the start of a Mastiff eruption looks. Later in the wait there was a smaller surge, just before the Bijou pseudo-pause.

We could hear something gurgling among the Southwest Vents, and that was the only activity on the platform in front of Giant. Back in early June I observed Emerald overflowing periodically.

Giant was much more vigorous than June. There were many surges to the top of the bite, and a lot of what seemed to be vertical surges, at least at the beginning.

It was hard to tell, but I don't think there was runoff from South Purple Pool.

Grotto was erupting when we arrived, and still going as we left. Spa was also active when we arrived.

After this, caught a Daisy eruption. Nice and strong, and it lasted 3-1/2 minutes.

Boardwalk staging site.

On the way back, decided I wanted to look at the new Sawmill Group boardwalk. See what over two months of work looks like. But first I got to experience the typical NPS pride in their work sites. I also like the way the blocked access to the signboard. It will be nice when they replace the one in front of Rift with wood. Except at the current rate, they will be fortunate to replace the remainder of the loop before it snows.