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Observations for 2019 September 13


With a full moon and clear skies, it was time to head out to Grand in the dark. Castle was slopping gently, and the walkway wasn't very wet, so it looked like there had been a minor eruption. At Grand, things were pretty normal. Heard an eruption of Sput D, but there was no overflow from West Triplet to accompany it. It was humid enough that everything was steaming heavily. I thought at one point Oblong was starting to erupt, but after a couple of minutes, no increase and no noise meant I was wrong.

It was only two Turban intervals before Grand started to erupt. The first burst lasted almost nine minutes, so wasn't surprised that there was a second burst, and that everything was quiet after that.

It was foggy for the next Grand eruption, which came after a couple of Turban eruptions. By that time the fog had cleared enough that it was possible to see the water column backlit.

With the day clear and warming, it was time to do something a little different. Did a bicycle ride down to Biscuit Basin. Was surprised when we arrived to find that there was actually a bike rack there. Getting across the bridge was a bit fun, because instead of a shoulder, there's a raised walkway, so a bike as to ride along the white stripe.

Did the Biscuit Basin loop, and got to see several eruptions of both Mustard Spring and Jewel Geyser. Not much else going on during the time we were there.

In the early after noon spent a couple of hours watching Turban. For the second hour, Turban and Sput D alternated, and the latter started just before the Grand eruption. This eruption had a long second burst, over two minutes long, with much of that time in Big Sawmill mode where it looks like it's stopping, only to have a jet rocket out. It's the kind of behavior the crowd loves, not knowing that it's keeping them from seeing another burst start.

There was one more eruption to attend after dark. The moon was out, but unforunately, there were clouds coming in, so that by the time Grand started, the lighting was subdued. The first eruption of Turban I saw while waiting lasted seven minutes, which was a pretty good indication that I was seeing the end of a Turban Delay. So I wasn't surprised to have Grand erupt two Turban intervals later. Again we got two bursts, the third such eruption of the day.

Also, for all four eruptions of Grand, it was followed by heavy overflow from West Triplet. It's beginning to appear that this is the normal mode, except when recovering from the weekly Rift eruption.