Observations for 2021 August 04


Headed out to Grand at dawn, with the expectation that Fan & Mortar would dominate the day. Got to Grand in time for what appears to have been a Turban Delay eruption. The following eruption of Turban had no overflow and the interval was short, which tends to confirm that. Grand erupted on the subsequent opportunity, showing that it can still have Two Turban Delays. This eruption had two bursts, with the first burst lasting nearly nine minutes. The pool drained and Vent & Turban quit immediately after.

During Grand, Penta had a steam-phase type eruption. I didn't see much of it, just the ending strong steam activity. The group was in a deep drain, with Sawmill rumbling, Spasmodic quiet, Slurp a fumarole, Churn out of sight and Oval erupting in the north vent.

From that it was time to head north to Fan & Mortar. All morning there had been no change in activity-- Angle Vent was on, with the other two Fan vents showing occasional, cyclical activity. After seeing some of this, I went over to East Sentinel. The activity along the north rim was taller and wider than yesterday, but there wasn't any evidence of an overnight eruption.

Following that, I got a Daisy eruption. It was short, 3m18s. Over at Splendid, the activity from Side Boiler started about 7 minutes later, shifting over to the Main vent about a minute later.

In the afternoon, went out to Grand and found Rift in eruption. Sput D and Percolator were also active. Sawmill was quiet. About 40 minutes later, Percolator shut off, while Sput D continued.

It was about then that I looked over toward Sawmill, and saw Uncertain in eruption. This was probably within a minute of the start, as Suzanne had been looking that way just before. What I saw of the eruption lasted maybe another 60 to 90 seconds. Sawmill started about 20 minutes later, and I saw that eruption end after the upcoming Grand eruption, for a duration of almost 40 minutes.

The One Burst Grand eruption followed shortly after Sawmill started, and lasted just under nine minutes. During the eruption Rift quit. We also got the Beehive Indicator call during the eruption.

As mentioned above, Sawmill quit shortly after Grand. At that time Belgian and Crystal were high, so Slurp was erupting as a geyser.

At this point, Fan & Mortar had their only change in behavior of the day. Angle vent finally quit for a few minutes, and a few splashes in Main vent were seen. Then it was back to the previous activity for the rest of the day.

Went back out to Grand at sunset. Sawmill was erupting, with the rest of the Group back in drain mode (low Belgian, Slurp fumarole, etc.)

About a half hour after I arrived, Turban appeared as if it was going to erupt. The lighting made seeing a little difficult, but it appeared that Vent overflowed during this time. The short Turban eruption duration tends to confirm an eruption attempt, as does the next Turban interval, which had no overflow from Grand.

The next Turban eruption looked like the one two earlier. This time Grand followed through. The first Turban start I've seen this visit. It was dark enough that the flashlights were out, but my attempt to see the start of Vent were thwarted by the steam. The first burst only lasted nine minutes, so a second burst wasn't guaranteed, but we did get one. There was no attempt at a third, even though Vent & Turban continued.