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.