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.