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Observations for 2019 September 17


It was a gray, cold dreary morning. Went out to Grand a bit early because the weather forecast said the rain was about to start. Instead it was blustery with only the occasional sprinkling that was just enough to need the umbrella, but it never lasted long.

Arrived to find West Triplet drained. It was even rumbling down deep a bit. The area with the sputs looked totally dead, with little steam. No change in Belgian or Crystal, but it seemed fairly obvious that there had been a Rift eruption. The longer double interval from Grand overnight tended to confirm this. I suspect it was after midnight, and lengthened the second interval.

Ended up waiting an hour through several Turban eruption intervals. Finally we got a Delay, which never looked like it wanted to erupt. The following Turban interval was promising, with Grand's pool quickly refilling. With the steam and wind, it was hard to see any waves, but when Grand had a couple of large boops similar to the other day, but not as tall, it was obvious it was going to erupt.

The first burst started to go into Big Sawmill mode, then quit with a duration of 8m45s. Have seen One Burst Grand eruptions that short in the past, but not this time. The water column easily outraced the steam column in the cold air.

Went back out in the late afternoon. Again, the forecast rain really hadn't materialized, but the wind and cold did. While waiting at Grand, the wind was usually to toward the north, but every so often the pool would become visible as the wind shifted to the south. Arrived to find West Triplet back to its normal water level, but there was no evidence of recent runoff as the channel was dry.

Shortly after arrival, West Triplet started to erupt. About 5 minutes later, Sput D joined in and both were erupting when Grand started about 16 minutes after West Triplet. This was another shorter first burst that stopped instead of going into Big Sawmill mode. And again the height of the second burst was well above the steam clouds, easily visible.

I don't know when Sput D ended, but West Triplet's last splash was seen late in the first burst. Percolator joined in during Grand's second burst, and quit shortly thereafter.

This behavior doesn't exactly fit what I was expecting. Previously, once the area recovered from Rift, the area would go into having frequent Sput D eruptions and West Triplet overflows. When West Triplet started, I was wondering if we were about to get another Rift eruption. The area is in flux, here at the end of the summer season when observers are few.