[Geysers] Fan and Mortar 8/19/2012

[jimscheir at aol.com]

Fan and Mortar erupted at 0903 today. The time details are as follows:

0833    River on
0858    High in lock
0901    Gold also in lock
0902    Large splash in Upper Mortar
0903    Upper Mortar start
0919    First pause
0921    Restart of Fan
0937    End    duration = 34 minutes

F&M for the last few days was having frequent "normal" cycles of River, then High and Gold, and then Angle. Some cycles were very brief, but many were 20 minutes or longer. Much of the time Angle shut off fairly quickly at the end and there was a quiet period before the next cycle. Over the last 3 days we monitored 6 "event" cycles during daylight hours with the typical splashing in Main and one or more River Vent pauses, but F&M refused to erupt during any of them. Upper Mortar usually showed a bit of water near the end of the event cycle. It also produced steam and noise commonly at the end of the event cycles and also from time to time during normal cycles and even between cycles.

This morning when a "normal" cycle began at 0833, I merely noted the time since it was nothing remarkable. There had been no splashing in Main, no River Vent pause, only some steam and sound from Upper Mortar that did not seem to differ from the typical of the last 3 days. High and Gold came on quickly so I did not note a separate time. Water levels were OK but not remarkable and they died down after a few minutes. Then suddenly High became 6-8 feet but variable. I called a warning on the radio to Gazers. Within 2-3 minutes High became a steady 8-10 feet or more and I called the Lock on High. Gold was avariable and weak, but it rose to a steady 6 feet and I called a Lock on Gold as well as High. Upper Mortar then had a huge splash and soon started the eruption so I called Mortar at 0903, not being sure if Fan would join. It took about 30 seconds for Fan to join in (still in the 0903 minute), with both Main and East starting together. Mortar seemed to be the one with the most energy as it was a very strong Mortar eruption. Fan seemed to me to be a bit under average, although it did put water over the boardwalk. There was little wind.

Several Gazers were able to get there just as the eruption started and others came within the first 2-3 minutes, but again there was very little warning. If someone had told me 5 minutes before I called a Lock on High that this cycle would lead to an eruption I would have said "fat chance".

This is the third F&M in a row to come with almost no warning.


Jim Scheirer




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