Observations for 30 August
On a normal morning, by 06:00 there's a certain amount of radio chatter. You get a lot of reports of eruptions on Geyser Hill or of larger features down basin, along with the occasional "switch to 5". This morning from when I awoke at 06:00 until 06:45, there was dead silence. I was wondering if my radio was mistuned or not working in some way, but Alan Friedman demonstrated that it was working just fine. He then got people down basin to confirm what all the vehicles in the Lower Ham's lot was saying (both the ones there and the ones missing). That Fan & Mortar had not erupted overnight.
It turned out to be a busy day. Grand had a nice two burst eruption, but the nearly three minute long second burst let us know that we could have had more.
Down at Grotto, there was quite a crowd waiting for an eruption of Rocket. Of course these were really people waiting for F&M. Over the period of about an hour, Rocket had several false starts before finally and reluctantly erupting. Unlike my experiences in the past, this Rocket Major did not start suddenly but at first looked like one of these "Rocket Minors" we'd been seeing.
After that, it was more Fan and Mortar. Some people stayed out there overnight, and so we knew definitely that there had not been any attempts at eruptions. After the Rocket Major, we were approaching 26 hours since the event yesterday. When I arrived, the people who'd been there were ignoring what to me (and others) looked like some strong activity from Fan. I asked, half-jokingly, "so tell me what its about this that looks so bad?" That when things got interesting. The vents of Fan really did look like the strong play that preceded eruptions back in the 1980s. After all the random "garbage mode", it was quite a difference. Tara belatedly put out a radio call, only to have F&M moments later force her retract it as the vents suddenly dropped in vigor and height. And went back to previous behavior.
Looking at the time, I decided that I could just as easily wait for any further events in the parking lot, and after a while, head out for the mid-day Grand. But first, a stop for Daisy seemed worthwhile. It was right after that eruption that I heard that splashing had been seen in Fan's Main Vent. Well, so much for my plans. Back to F&M. By the time I got there, the splashing had pretty much stopped. It wasn't long, however, before the Fan vents started, and they didn't follow the pattern of the last day-and-a-half. This time they were taking their time. Instead of Gold Vent following High vent within a minute, we saw several minutes of High splashing. Between these splashes the water level, just below the overflow lip, could be seen from the right locations. Finally, when Gold did start, the activity of High stayed vigorous, and its height seemed to increase.
By now I was getting to experience activity which I'd not seen before. In years past, when I'd seen a start, once the "lock" stage had been acheived, it was only a matter of moments before the eruption began. Here the lock seemed to drag on and on. In a few minutes High vent was erupting at at least 8 to 10 feet, with Gold going 4 to 6. Angle had turned to steam and still no eruption. Then Main vent began to have small surges, each one bigger than the previous. Even after the East vent began erupting it took Main about ten seconds to join in.
Mortar's vents showed a bit of water, then shut down. Not even steam. With a fairly strong breeze from the west, this gave us a clear, unobstructed and dry view of Fan for several minutes. Then suddenly Mortar came back to life, and everyone who'd tried for that closer clear view became wet. All three of Mortar's vents seemed to come and go independently of each other. While getting wet from Main vent meant getting hit on the fly by warm water, from Mortar it was a cold, soaking mist.
With the considerable warning, and it being the start of a three-day weekend, there was quite a crowd of gazers there. No census,but wouldn't surprise me that the number was close to one hundred. There must have also been and equivalent number of visitors who wandered up during the preliminary excitements. Fortunately Riverside wasn't near an eruption, because adding in that crowd would have made the walkway impassible.
The F&M eruption was short, only 29 minutes to the last water, and then there was a final huff of steam from all the vents. During the eruption we also got activity, of a sort, from South Norris Pool. The water level rose and was accompanied by boiling along the southwestern edge. It was almost an eruption.
After the eruption it was time to head for the Grand eruption which I had thought would be my place of waiting for the event. Turns out Grand had other ideas, as just as I was about to get on the bike to head out, the call comes that Grand has started. A 6 and a half hour interval. I did get there in time to see the second burst, which was perfectly timed just as the wind paused. An already tall burst was not cut down by wind.
Next up was Penta. It started a steam-phase eruption shortly after the Grand eruption. Most steam phases aren't really that interesting, but this one put out a lot of water. The runoff eventuallly reached beyond the walkway. The Top vent was roaring loudly, at times putting out nothing but steam. Meanwhile, Oval started to rise and burst to several feet. This activity lasted several minutes before the water level resumed its usual Deep Drain levels.
By this time it appeared that everything of interest that could erupt had done so, but not quite. After erupting some time during the night, Beehive had what had to be a short interval to finish off the day with a nice, but wind reduced water column.
Meanwhile, down at Giant, Bijou is starting to have shutdowns and Mastiff is showing that it can have "bathtub" hot periods. It wouldn't be surprising for Giant to erupt some time in the middle of the coming week. It's been iknown to do that in the past.
The weather prediction was for increasing cloudiness and increasing wet, and by sunset that had become obvious. But with the clouds came a warmer night. During the wait for the nighttime Grand, I never even felt the desire to dig out all the coats and blankets I would have put to use on a more typical night (like the day before...) We were also treated to occasional heavy gusts of wind and periods of dead calm, and a few spits of wetness.