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Observations for 2021 September 12


Wasn't planning to head out in the morning, but just as breakfast was ready to eat, got the call about Beehive's Indicator. Had plenty of time to get out to see the Beehive eruption which was in dead calm conditions. I didn't see the Base Vent do anything during the eruption.

After that, did head out for Grand, a ten minute One Burst Eruption followed by West Triplet erupting.

With nothing much else going on, went out to Lone Star. Arrived at the end of the first minor eruption. Twelve minutes later, another eruption started. About a minute in, the size and power seemed to increase dramatically, and water could be seen coming from the small vents on the left size. Then, after only two and a third minutes, it all quit. It was 26 minutes before the major eruption started, which was an interval of about 3h15m between the major eruptions.

Back at Grand, arrived with Percolator in eruption. This is moderately unusual, and indicative of West Triplet starting soon. But West Triplet didn't start until an hour-and-a-quarter later. During this time there were just a series of non-descript Turban eruptions.

Grand started shortly after West Triplet. The One Burst Eruption lastest 10-1/4 minutes, and there was water in Grand's vent for about twenty seconds before it drained. Then right after the end, Rift started steaming, so we stayed around to watch the water start down the runoff and go under the walkway.

Over at the Sawmill Group, there was a deep drain in progress. Tardy was having a series of single bursts, two or three per minutes, followed by a longer eruption lasting about a minute with a similar pause before the start of the next series of single bursts.

Did get to see Tilt start while waiting for Castle. Castle waited until the sun had set before erupting. We had left maybe a couple of minutes earlier.

Went out to see the midnight One Burst Grand Eruption, which lasted about eleven minutes. As expected, Belgian and Crystal had risen to near normal height, in response to Rift, and were starting to drop again.


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Observations for 2021 September 11


If we had gone up to Norris, we would have probably been exiting the Gibbon Canyon when New Crater/Steamboat erupted. I had just arrived at Fan & Mortar, and it was a relief to get the message from Suzanne, knowing we didn't need to worry about Norris for the rest of the trip.

It had rained overnight, and was still mostly overcast. Cool and damp, as it didn't have a chance to get cold overnight.

As it was, I was on the phone with her when suddenly Upper Mortar had a nice rumble. The High and Gold Fan vents were looking good when the call started, and now, moments later, they looked great. I hung up and actually got on the radio to issue a "heads up" call.

The activity looked a lot like the previous eruption, but Angle was not active, and Bottom vent had been splashing when I arrived. Even if it was early in a cycle, people needed to be informed. Over the next ten minutes, the vents only waned a couple of times, then immediately came back strong. Finally, Angle joined in, and by then High was as high as last eruption's preliminary activity. When the Frying Pan finally started, there was little doubt that something was going to happen.

Upper Mortar never really surged until, suddenly, East Vent took off like last time. Unlike last time, the other vents quickly joined in. Unfortunately, the wind, which had been blowing the steam toward the river, shifted and was now toward the benches. So Mortar was clearly visible, but Fan was lost in a mass of steam.

After the eruption, a quick check at East Sentinel showed no real change, other than the one overflow I saw was not followed by any boiling from the South Rim.

The morning Grand was the second observed two burst eruption in a row. It started three Turban intervals after a Turban Delay Interval. There was a definite false pause about 1/2 minute before the end of the first burst, and the whole eruption lasted just over ten minutes.

Later in the day, came out to a Sawmill Group that had relatively high water. Slurp was completely quiet. Penta was splashing slightly, and Belgian and Crystal were both down about 5cm. West Triplet, Percolator and Sput D were also in eruption as I arrived.

The first Turban eruption I saw had an unusual explosive start. Suddenly a thin jet of water was propelled about three meters above the rim, followed by several seconds of quiet before the usual boiling surges began.

Another fifteen minutes after that, Rift started. At that point Grand was full, but stalled out for the next fifteen minutes, giving us another Turban Delay Interval. Fortunately, Grand had its third consecutive observed two burst eruption just two Turban eruption intervals later. At first it was hard to see the pool as Grand paused, then the steam parted with the pool full of churning water. As with this morning, the second burst was short.

Following that, spent some time in a Sawmill Group that still had high water. It had been higher earlier, as the runoff from Spasmodic was still wet. Watched Penta splash around for a while.

Finally, from the bike rack, watch a Bulger major eruption, but no indication of any activity out of Bulger's Hole.

Went out to illuminate a nighttime Grand. It was a One Burst Eruption after Delay that cause the eruption to be two Turban eruption intervals later, and the eruption lasted less than 9-1/4 minutes.


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Observations for 2021 September 10


Got out at dawn to find Fan & Mortar didn't erupt overnight. But over the next few hours, I ended up going back and forth between there and Castle because it insisted on looking good enough. Watched Turban and Sawmill start from the bike racks, just in case needed to run back north. When I did head over to Grand, I saw the One Burst Eruption start from Sawmill (and would have recorded it if I had hit the right buttons).

Also did a spot check of East Sentinel, and it looked unchanged.

A windy day, so went up to Daisy at a four-and-a-half hour double interval, and still needed to wait a half-hour. Otherwise everything there seemed normal, with Daisy lasting 3-1/2 minutes.

Mid-day wait for Grand had West Triplet start before Grand. We did get a second burst, one lasting over two minutes

After that, part of afternoon was spent at East Sentinel, where it still looked unchanged from the last few days.

Fan & Mortar didn't do anything after the morning's events until it was time to head to Grand, when it had a weak event. I watched a couple of Turban eruptions from the bikerack again, just in case it picked up, but it didn't.

Over at Grand, both Percolator and Sput D were active. West Triplet was not near overflow. This has been a sign of Rift in the past. After about an hour, West Triplet finally did start, but it was a short duration eruption and Rift stayed quiet.

Grand itself was getting into that weird mode where it had a Turban eruption interval of less than 16 minutes, and where the overflow starts much earlier than usual. Fortunately, there had been no delay, so the interval for the One Burst Grand eruption was about 7-1/4 hours. It was a twelve minute long duration, which helped drain the batteries of several lights.


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Observations for 2021 September 09


Spent three more hours at Norris, confirming that nothing much has changed with New Crater/Steamboat. Just as we were about to leave, of course there was a nice minor. We waited another ten, just in case there was a followup, but nothing happened.

We took our time in the parking lot, putting things away and getting organized. I had just backed out of the parking space and was weaving my way among the people waiting for others to leave when we heard a radio call for another good minor. Made the executive decision that there was no way we were circling around and parking and heading back out. Was the right decision, in that after a couple more nice events over the next hour, nothing much happened.

On the way back from doing laundry and grocery restocking in West Yellowstone, decided to stop in at Great Fountain. It appears it started just after we'd passed that spot on the road where it and White Dome are visible, and by the time we arrived at the parking area. Miraculously, there was a parking spot right across from the walkway. So watched the rest of the first series, and the next two. The second was poor, while the third was adequate.

But the most pathetic thing about that eruption that several hours later, I noticed that no one had reported anything about the eruption, so I had to add in our arrival time to GeyserTimes.

A bit later on, went down to check on East Sentinel, which hasn't changed in activity since the major activity earlier in the week. Still cycling every 19 to 20 minutes with all the activity along the North Rim.

Returning from there, I noticed that the Frying Pan was steaming at Fan & Mortar, and there was the appearance of the end of a normal cycle. So I headed off to Grand.

Walked up on another deep drain the the Sawmill Group, with even Slurp quiet. Saw Old Tardy start, and saw Percolator and Sput D erupting. Then Sawmill started.

Twenty minutes after I had passed by Fan & Mortar, Suzanne was doing the same when she saw splashing in the Main Vent. Even though it was a little over two days in the interval, I left Grand because I know Fan & Mortar can have intervals that short, and it's been doing strange things this year. Turns out the Main Vent splashing went on for a long time, and during that time Lower Mortar was showing the first "fuzz ball" activity in several intervals. The Frying Pans and East Vent were also steaming slightly. Bottom Mortar had a series of eruptions, but when the Fan vents started, they didn't look encouraging, and by the time the Frying Pan started, it was obvious that there was not going to be an eruption.


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Observations for 2021 September 08


With Fan & Mortar out of the way, it was a day to waste at Norris.

Arrived at dawn, and left twelve hours later. There had been delayed, days old reports (which no one had seen until yesterday) which said that New Crater/Steamboat was looking good. That wasn't what we saw. Infrequently there would be a short, strong minor with lots of water coming out of South Vent, but in only one case was there a follow-up within ten minutes. The "bounces" and "vertical" from North Vent happened a lot, and seem to be of no consequence. Toward the end of the wait, these minor eruptions were happening about a half-hour apart, which resulted in our staying an extra hour. Just in case.


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Observations for 2021 September 07


Once again, got up while still dark to check on Fan & Mortar, and once again, they hadn't erupted. So sat myself down to watch and listen to Angle Vent chug away for an hour, until it was time move over to Grand.

It was another double interval, so may have gotten there early. But the second Turban eruption was a Delay Interval. The only good thing about it was that it meant that the eruption would be under less steamy and brighter conditions.

It only took two Turban eruption intervals before the start of another One Burst Grand Eruption. And the conditions were excellent, as even the smoke hadn't settled in yet.

After reconfiguring and having some breakfast, went back out to Fan & Mortar. Still nothing much happening. The big entertainment was about a dozen duck appeared down river, and made their way to where the North Chain runoff channel used to be. There they landed and then settled down to sleep. They were leaving as I was leaving, about 1-1/2 hours later.

Went over to Grand for another eruption, and probably arrived at the end of a Turban Delay Interval. This eruption had a long duration, and the next Turban eruption had no overflow from Grand. Grand finally erupted on what was probably the fourth Turban interval, and the streak of One Burst Eruptions continued.

From there, we considered going back to the cabin, but instead decided to return to Fan & Mortar and kill some time there. Tara Cross was the only other person there. We killed some time as an uninteresting cycle progressed out at Fan. But about twenty minutes into the activity, Fan's High vent suddenly seemed to pick up. So much so that we decided that everyone else spread around the basin (from Artemisia to Grotto to Geyser Hill and the Lodge) needed a "heads up" alert, just in case this resulted in an eruption.

A few minutes later we saw a splash from Main Vent. This is the first time I can remember anything like this happening, which also meant that I had no idea what could happen next.

We saw another splash as the activity from High Vent became strong and continuous. Gold Vent was also pouring out water and itself nearly continuous. High was acting and looking a lot like Vent Geyser as it starts. I started taking video, as the activity continued on for about three minutes. By this time High was erupting to about six or seven meters high.

Then the water in East Vent welled up and it was erupting to at least ten, if not fifteen meters high. This activity lasted (according to my video recording) about 22 seconds, when first Lower Mortar, then Main Vent, and finally Upper welled up and out and into full eruption. This activity started about nine minutes after the first radio alert.

The wind could have been a little better, as the walkway from the middle of the bridge to Spiteful got soaked. I got soaked, and the initial surges from Main are still quite warm.

At some point Spiteful stopped, and became calm. At one point after Fan & Mortar had ended, it had a brief eruption from the back vents, with the rightmost vent throwing water horizontally a couple of meters to the left beyond the rim.

Later in the day, I went out for the early night eruption of Grand, only to walk up on Sawmill starting as I passed Scalloped. Then as I got up to Sawmill, I saw the start of a Penta steam phase. The group was in a deep drain. There was a lot of noise from the Main Vent, and the bottom Right Vent was occasionally spraying water onto the walkway. This activity lasted about four minutes.

The last Grand of the day was another One Burst Eruption. Again, based on Turban durations and intervals and Grand's lack of overflow, I guess that it was a Two Turban Interval Delay. Also, the eruption only lasted a bit over nine minutes, and even with the bright light, I saw no indication of a second burst.


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Observations for 2021 September 06


Got up while still dark to check on Fan & Mortar. They hadn't erupted, and in the brief time I was there, all I saw was splashing from Angle Vent. So it was off to Grand.

It was light enough that the flashlight was no longer needed, and warm enough that the walkways were not frosted and slippery. It was another One Burst Grand eruption but it also closed a short double interval.

Watched East Sentinel for a bit, long enough to see a cycle of about 20 minutes between heavy overflows. Then spent three hours at Fan & Mortar. At first it was garbage mode, but everything got quiet for about eight minutes before Fans vents turned on. Later there was a hit of steam from the frying pans, and what seemed like heavy steam from Upper Mortar, but nothing much came from that. Then it was back to garbage mode, with Angle having minor blips every minute or two, and the other vents coming on strong for a minute, then quitting for a few minutes.

The midday Grand eruption had a Turban Delay with a small Grand boop followed by about five minutes of the pool slowly dropping. It was three more Turban eruptions before Grand started, and unlike many Delay starts this year, it was initiated by Grand.

The rest of the afternoon was devoted to killing time down basin. Toward sunset, it was time for Grand again. This time there was not only no Turban Delay, but the One Burst Eruption started with the sun still barely above the horizon.


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Observations for 2021 September 05


Visited East Sentinal early in the morning for about 40 minutes. The North Rim vent cycled every 15 to 20 minutes, briefly having a heavy overflow and some surging, then dropping back down for the next cycle.

Over at Grand, the walkways were icy, especially in the shaded areas (or where shaded by people sitting on the benches). I think Rift may have erupted a few hours earlier, as both Crystal and Belgian were high, and Slurp was in a wet eruption.

While waiting, I saw Bulger start, the first activity in days. A bunch of us quickly went over there and got to see Bulger's Hole fill and erupt. It still does its spitting and pausing. It also made noises as it drained.

Grand itself was another One Burst Eruption, starting at the end of a Tuban Interval Delay. A ten minute duration resulted in Vent & Turban quitting.

Then spent a couple of hours back at East Sentinel, where it still didn't do anything, just more cycling as seen earlier.

Grand then had a long interval for no good reason. It finally erupted on a 32 minute Tuban Interval Delay, where the pool seemed to be dropping at Turban started. It then came up and started flooding the area. A nine minute duration was enough for the pool to briefly refill before dropping for good. At least Vent and Turban continued.


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Observations for 2021 September 04


Thw walkway past Rift had a nice coating of frost in the morning, as did the benches. It got heavier as I waited through the Turban intervals after a long Turban Delay Interval. It wasn't warming up as there was a thin layer of clouds that had replaced the smoke. But the One Burst Grand was nicely visible as the steam was being pushed to the south.

Toward noon, I decided that checking on Fan & Mortar was a good place to waste some time. Over 45 minutes I saw what appeared to be "garbage mode", where the Fan vents come and go, look good at first, but there's never any prolonged gap or activity from Mortar. So decided that I should check on East Sentinel, then head in.

As I approached, I saw a larger than usual steam cloud from East Sentinel. It appeared that I was seeing the activity between minor eruptions. The vent was empty as I arrived, while there was some jetting from the south rim toward the north inside the vent itself. There was steam coming from the small vents to the south of the crater.

Empty crater of East Sentinel

Over the next few minutes the activity of the vents picked up, leading to a small minor eruption from an empty crater. About ten minutes later there was a second such increase in activity.

Then water became visible at the bottom of the vent, rising quickly. It got as high as about 1-1/2 meters from overflow, then started fluctuating. Around this time thumping could be heard. The pool finally rose to about 1/2 meter below overflow, when the activity shifted from the south to the north.

Now some horizontal jetting could be seen well under the shelf. The small vents to the south had stopped steaming by this point. After a while with no change, left the area on the assumption that it was in a refilling mode.

From there it was time for Grand, and another One Burst Eruption. That was immediately followed by the start of Beehive's Indicator, so a quick trip to Geyser Hill was in order.

A few hours later I decided to check on East Sentinel and Fan & Mortar again. I arrived at East Sentinel to find that the activity had shifted again, with the south rim boiling vigorously. Over the next few minutes, the water level in the crater rose as the activity increased. Water was pouring out of the runoff slot, while the south vents were jetting a couple of meters in height, including some horizontal activity to the east (the mostly dry channel at the front).

This activity lasted about three to four minutes, then the water level dropped and the boiling subsided. Over the next hour, the water level would rise to overflow, then drop. Eventually the overflow was so heavy that the runoff notch couldn't contain it, and water started running south over a low spot in the rim. At that point, surging started again, and we got another eruption, stronger than the previous. This one lasted under three minutes, and once again the crater water level dropped about 30cm at the end.

East Sentinel minor eruption

Following this the rising and falling started again, but I decided that it would be nearing dark before the next attempt, and left.

Did go out for the after sunset One Burst Grand eruption. This one lasted over twelve minutes, and featured a couple of false pauses, one at around the 8-1/2 minute mark, the other a few seconds before Grand finally quit.


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Observations for 2021 September 03


Plans for today were completely ruined by the eruption yesterday evening of Fan & Mortar. It didn't help that Grand had a long double interval.

So the day really didn't begin until late morning. Rift had been seen in eruption a few hours earlier, so when I got to the Sawmill Group, I wasn't surprised to find Belgian and Crystal Springs full. Slurp was erupting in its Wet mode, and there was runoff well beyond the walkway. The Grand Group was in a deep drain, with Spasmodic's main vents almost out of sight.

I'm coming to the conclusion that Belgian and Crystal are rising in response to Rift, and that process begins or peaks several hours after Rift starts. In the last week I've seen this on several occasions, and I have been watching all this visit and not really seen many times when those two are full. Another indication that things have changed from the past, as years ago an eruption of Rift would draw the two down 3 to 6cm, not cause a rise.

Did a walk around Geyser Hill to kill some time, with nothing much happening there, either. By the time I got back Belgian and Crystal had dropped, and Slurp was back into fumarole mode.

The One Burst Grand Eruption after noon fairly undistinguished, other than it being started by Turban. From there,I had just passed the Lodge on my bike when the call for Beehive came over the radio. Went over for a nice, but crowded eruption.

Headed out for Biscuit Basin, but realized it was getting late, so only made it as far as Cauliflower. Saw a nice eruption, maybe reaching 1/2meter for a few seconds.

On the way back, made the mistake of looking at Fan & Mortar. Bottom Vent was starting to erupt, and Main Vent was steaming heavily. Within a minute or so, Bottom was in eruption, and we'd seen several splashes in Main. A few of those splashes were huge, with definite shape of the erupting water being thrown far into East Vent. I decided that a one day interval was extremely unlikely, and didn't let myself get sucked in.

Grand had a Turban Interval Delay, and waited just long enough to erupt just after the sun could no longer illuminate the water column. We did get a second burst, but it was a short pause, and one of the weaker second bursts I've seen in quite a while.

To cap off the day, waited for Castle, and watched it go into steam as it got dark. The pausing stopped around the seven minute mark, only for there to be a couple of pauses about six minutes later. But then the water became continuous.


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Observations for 2021 September 02


Got a late start to the day, after last night's late Grand eruption. It didn't help that Grand followed up with an interval well over seven hours.

Went down to check East Sentinel. No change since last visit. Didn't stop at Fan & Mortar as it seemed to early to get sucked into that time sink.

From there it was back to wait for Grand. The water levels in the Sawmill Group were high, with Sawmill in eruption. Spasmodic had been in overflow recently, as the runoff channel was still wet. Slurp was actually quiet, with just some gentle steam coming from the vent. Belgian & Crystal were down perhaps 1.5cm.

West Triplet had finished just before I arrived. Only had to wait one Turban eruption interval for the One Burst Grand eruption. It featured not only a boop well before Grand started, but a significant pause pause about nine minutes in. Just at the time when it was obvious there was no longer a chance for a second burst. Slurp was still quiet as we left.

Heard the call for Beehive, and got out there with plenty of time, as this Indicator interval was nearly 19 minutes.

Then time for another Grand wait. The Sawmill Group was back into a deep drain, with Slurp a fumarole, and Belgian and Crystal down about 3cm. I arrived to a Turban eruption, a long one lasting 5-1/2 minutes. I suspicious that I had just missed a Turban Delay Interval were confirmed when the next interval had no Grand overflow.

Then ten minutes into that interval the call comes in that there is splashing from Main Vent down at Fan & Mortar. Fortunately, if there was a Delay, it was only a Two Turban Interval Delay, as Grand was suddenly full and having waves and overflow from Vent. Once again, it was a One Burst Grand Eruption, with Vent & Turban quitting even though the eruption was barely 10-1/2 minutes long.

With that out of the way, it was time to head down to Fan & Mortar. We had already decided that that was going to be our destination after Grand, to do a quick check on early activity before sunset.

But as the activity progressed, it became obvious that despite the 2-1/2 day interval, this was not going to die down. The Frying Pans became active much sooner than usual, and were quickly followed by increased noise from Upper Mortar. The vents on Fan by then were erupting continuously, with High Vent up to 3 or 4 meters high.

There was an aborted attempt at a start from Upper Mortar, then a second, longer attempt. After about ten seconds, this one died down, then suddenly every vent started erupting. The wind was mostly cooperative, and with it being late evening, all the vents were backlit nicely. Between the vents was usually a good place to see everything.

During the eruption Norris Pool rose to slightly above its rim. At some point Spiteful's back vents stopped, with the pool calm and pouring out water from a level perhaps 1-2cm higher than usual. Toward the end of Fan & Mortar's eruption the back vents of Spiteful reactivated briefly.

After this eruption, did a quick check of East Sentinel. There was no change from this morning.


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Observations for 2021 September 01


Another day to visit Norris. New Crater/Steamboat looked moderately interesting the first hour or so, with infrequent surges from South Vent that send a flood of water down the runoff, but during the second hour, that activity had subsided. Over at Collapse Crater Spring, the eruptions were about six minute apart, and not as strong as during the previous visit.

Back in the Upper Basin and in the cabin, it was time for lunch. I was chowing down in the cabin with the door open when I saw a small dog without a leash run by. I got up to see what the owner looked like, and saw no one. The dog was still trotting away toward the south. It looked like an oversized chihuahua, and it occurred to me that I had just seen Iris, who had escaped last week.

I contacted the VC who in turn contacted the Comm Center, who sent out one of the Law Enforcement rangers. I met him when he arrived with the area, and described what I'd seen. He was still patrolling the area as I left for Grand.

Out at Grand, maybe a half hour later, I heard that they had a loose dog in custody, one that matched the description of the one I saw. They also believed it was the missing Iris. So I await my reward for putting them in the right position to make a successful capture.

At Grand itself, it was another dull One Burst Grand that lasted just long enough (about ten minutes) to know that there wasn't a chance of a second burst. From there, went on down to East Sentinel, where things didn't look much different that they had yesterday.

Had just finished getting together something to eat when got the call for Beehive's Indicator. Shove the food into the microwave, and headed out. Was approaching Anemone when Beehive started, but fortunately, the wind, while string, was steady and no one there got wet.

Went out for the evening Grand to find Rift in eruption. It appears Rift is now having an effect on Grand, with Grand not even trying to erupt until well after Rift ends. As in the other night, the intervals and durations for Turban eruptions gets shorter. For this Grand eruption, the Turban interval prior to Grand starting was less than 16 minutes, with overflow well before that. Also, Grand didn't start until 1m44s after Turban. The first burst was just over eight minutes, but the second burst was long, with once again Vent & Turban stopping on a relatively short duration.

Also of interest is that once again, a couple of hours after Rift ended, Belgian and Crystal were full, with a wet Slurp eruption in progress.


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Observations for 2021 August 31


Busy morning. First I had to go down to check on Fan & Mortar since there had been no reports of any activity or status since sunset yesterday. (Some people can't be bothered to report the obvious while on their way to look at "the sun dress.") From Culvert I could already see that the bridge was wet. The wash zone extended all the way beyond Spiteful and Norris Pool. The vents were completely quiet, so it had been several hours, but it also hadn't been before midnight.

From there, did a quick check on East Sentinel and discovered it too had erupted, and recently. The water in the vent was down about 1/2 meter and calm and clear. The large catch basin was still steaming gently. It looked like the grass to the south was pushed down more. If not a major eruption, it was a pretty powerful minor.

On the way back, as I was rounding the curve below Oblong, a bison started to step out of the trees as I rode past. I was gone before either of us could react.

While tying up my bike, I saw that Bulger was in a strong, major eruption. As I walked down that way, I saw Bulger's Hole start up, too. Height was at least a meter above the rim, and lasted for well over 1/2 minute.

Finally got out to Grand, which was my intention when I got up this morning. Had just set the pack down and wiped down the bench when I saw a large boop from Grand. A couple seconds later the eruption had started. Was another One Burst Grand, but there was just enough breeze that the water jets were visible from West Triplet area.

With nothing much going on, it was a good time to visit Lone Star. We arrived just as the eruption was making the transition from water to steam, probably the time with the longest wait for the next eruption. Decided that we'd rather not kill a few hours there, and returned.

When walking out to the noontime Grand, I noticed a jet of water coming from Penta. Sawmill was in eruption, and Penta was having a weak steam-phase eruption. There were a few more jets of water from the Top Vent, and a lot of noise from the vents, but there had been no water discharge. The Sawmill Group was in a deep drain, with Spasmodic's water levels almost out of sight.

The wait for Grand was a long series of non-descript Turban eruptions and intervals. As the seven hour mark was passed, we had short Turban interval of just under 16 minutes with a short Turban duration. I was wondering if we were going to get a repeat of the other night, but it turns out we got a One Burst Grand eruption with the next Turban eruption start.

By then it had gotten very windy. Stopped by Daisy at the 2-1/2 hour mark, and decided instead to check out East Sentinel. It had recovered from this morning's activity, with the vent discharging water. All the activity was back along the northern rim, with some of the boiling going well over the rim itself.

Returned to Daisy, and it still hadn't erupted. Ended up being an interval well over three hours long.

Finally went out to Grand after sunset. Never saw a Turban eruption, but did wait close to half an hour. It was one of those time when once Turban started, there seemed little doubt that there would be another One Burst Eruption. The only interesting part of the eruption was during the wait, when a bison went through the Sawmill group on its way to the river.


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Observations for 2021 August 30


After last night, I still could have gone out for the next grand eruption. I woke up before it occurred, but decided not to do that. Turned out to be the correct decision, as Grand had a One Burst Eruption about ten minutes later. Not enough time to get dressed and down the biketrail.

The day mostly consisted of a couple of events at Fan & Mortar and a couple of One Burst Grand eruptions. The Fan & Mortar events followed the same pattern-- splashing in Main Vent during a pause (or in the second case, two pauses) followed by no real followup from Upper Mortar. In both cases, the events, took place well before it was time to head to Grand.

The Grand eruptions were different. The midday eruption came on a Turban Delay Interval, and had over four minutes of boops out of Grand before it finally, reluctantly, erupted. This eruption lasted just under ten minutes, and unlike the eruption last night, Vent & Turban continued. The second had no delay, was just a long interval. It started with Turban erupting while Grand was overflowing heavily. It lasted close to eleven minutes and Vent & Turban did quit this time.

Before the second Fan & Mortar event wait, spent some time down at East Sentinel. It has changed since I was last there. It was boiling heavily and irregularly up to two meters along the southern edge of the vent. The water level was fluctuating between heavy overflow and down about 10cm. It might be having actual minor eruptions from that area, but I didn't see one in the hour I spent there.


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Observations for 2021 August 29


Just after midnight on perhaps the first clear night of this visit. The moon was at last quarter, so there was plenty of light for a walk from the cabins out to Grand via Geyser Hill. Haven't done that in years. No need for bear bells because the walkway between Lion and Liberty is so noisy. Once we got onto the plastic walkway, we could feel the ice starting to form.

Probably arrived during a Turban Delay eruption. The next Turban eruption had no overflow, and the subsequent one was strong, but short. Grand finally erupted on the fourth Turban eruption after we arrived. During our wait, we did get to hear a full eruption of West Triplet, but no followup from Rift.

The Grand eruption was steamy, but without wind, so occasionally we could see the water column backlit by the moon. Finally decided to try illuminating it, and again, because of the wind, there wasn't much success from a variety of positions. By then the ice was forming on the benches along with the walkway.

The morning was spent taking care of various tasks in anticipation of another wait at Fan & Mortar starting tomorrow. Did arrive back in the area to find Grand hadn't erupted in the afternoon, so attempted to get out there. I got to see the start of the One Burst Grand from just below Crested Pool.

Went out to the sunset Grand with the assumption that it could erupt after dark. Saw Turban erupting as I was tying up the bike at Castle, so I know that the next interval was more than long enough to be a Turban Delay Interval. Percolator and Sput D were active, so I wasn't surprised when West Triplet started right after. But it only splashed for a few seconds, then receded back into the vent, and out of sight, leaving a high water mark.

It was forty minutes later that West Triplet started again, and this time continued. It took nearly four minutes to finally reach overflow. Midway through this eruption, two intervals after the Turban Delay eruption, there was another strong attempt at Grand erupting. It was getting dark, but still possible to see the pool was full and probably having waves.

Then Rift started, and Turban started having a series of eruptions that got shorter in duration and interval as the night progressed. Sometimes it looked like Grand's pool was steamier and possibly full. Most of the Turban eruptions started out weak but a few started strong, but most durations were just over three minutes. The intervals were getting down below 16 minutes long.

Then, shortly before midnight, and 4-1/2 hours after the Turban Delay Interval, there was a Turban interval of less than 14 minutes, and the eruption lasted just barely over two minutes. Around this time I checked Belgian Pool and Crystal, which were both full, with Slurp in full wet mode and water running down the runoff channel.

The next Turban was almost as poor, but finally we got a interval that lasted well over 17 minutes and Grand finally erupted. The moon, less than a quarter, was lighting the top of the water column, making backlighted viewing easy. But the eruption lasted only 9-1/2 minutes, and then, Vent & Turban quit.

This Grand interval was approaching eleven hours. A few weeks ago, the data logger reported that there was an interval well over eleven hours under similar nighttime circumstances. At the time, I suspected it was a double with the middle one missed. Looks like it was probably a real interval.


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Observations for 2021 August 28


In the morning, Little Squirt was reported to be in eruption. By the time I got there about an hour later, it had finished much earlier. But the warm ground frying pan area did have some steam and noise coming from it. I suspect the activity we saw back in May was due to the wet weather drowning the warm ground. But it does indicate that the ground there has potential to develop further.

Arrived at Grand with Percolator in eruption, and Sput D joined in shortly after. So no surprise that West Triplet started about a half hour later. Which led into the start of Rift just before Grand. This was another Turban initiated eruption, after a couple of longer Turban eruption durations and intervals. Might have been some sort of delay before I arrived.

There was a report of East Sentinel erupting shortly before I went out, so after Grand, went down to check it out. Definitely something happened there. The pool was murky and mostly quiet, with just a slight boil along the southern edge. The pool was below overflow when I arrived, but rose quickly, which could be just the normal cycling. There were wet pools, but not as full as I would have expected after a couple of hours. The northern formation was completely dry, indicating no boiling from the alcove area. And there was just a hint of the smell of low tide.

At Beehive, we had several bubbling sputs -- Close-to-Cone, South Bubbler, West Bubbler -- before the Indicator finally started. There was little wind, so the water column was tall with only small segment of the boardwalk getting wet. During the eruption, the Base Vent also was active.

Grand had a Turban Delay Interval, and just before the second Turban eruption after that, Bulger had the only second eruption I've seen this visit. It also included an eruption of Bulger's Hole. A check after the Grand eruption showed that Crystal and Belgian were down about 5cm, and Slurp was barely steaming. Sawmill had also quit about fifteen minute prior.

Grand erupted almost immediately after Bulger. If the One Burst Eruption had taken place one Turban eruption interval later, the sun would have been set. As it was, there was no wind, and we got a nice rainbow once Vent started. Around the nine minute mark there were several slowdowns that weren't long enough for false pauses, but were enough to ensure the eruption continued.