[Geysers] Fan & Mortar--The strangest start I've ever seen

[lynn stephens]

From:  Lynn Stephens   Date:  8/19/04


Fan & Mortar erupted at 1748 this evening (8/19/04), an interval of about 2 3/4 days.

Dean Lohrenz was on his way to Artemisia when he called Main Vent splashing and Bottom Vent already in eruption.  Michael Lang went down and called River Vent start at 17:22, with Gold on shortly thereafter.  At 4 minutes in Michael said water levels looked good, then a few minutes later he said they looked abysmal.  Ralph Taylor and I had stopped at Grotto Fountain.  Thankfully, South Grotto Fountain started about the time Michael called water levels were recovering.  About that time the sky opened up with a hailstorm.  (My toes are still stinging because I was wearing sandals instead of shoes.)

When Ralph and I arrived at Fan & Mortar, High Vent was goint 6 to 8 feet high and Gold Vent was about 4 feet high.  Somebody said something about a lock, but I said Angle Vent wasn't participating--it was in steam phase.  This continued for several minutes.  (Because of the hailstorm, no one was writing down the details.)  As High and Gold continued going crazy, and East Vent wasn't steaming at all, Main Vent started to splash.  Yes, I wrote Main Vent--not Upper Mortar.  Main Vent splashed weakly three or four times.  Then Angle changed from steam phase back to water.  I'd never seen Main Vent splash 20+ minutes after the start of River Vent.  But then I'd never seen a 2/3 lock either.  Then Main Vent started filling the vent and splashing 2 feet, 4 feet, 6 feet high.  I was (as usual) yelling at that stupid pile of rocks telling it it couldn't not erupt after that type of Main Vent activity.  Main Vent had 5 or 6 of these vent filling, overflowing splashes before East Vent 
 finally started the eruption at 17:48:10, 26 minutes after the start of River Vent.  Two or three large rocks came out of Main Vent at the start of the eruption.

East Vent didn't hit the walkway at first.  Shortly after East Vent took off, Lower Mortar surged and sent a tremendous amount of overflow out the side.  Then both Upper and Lower Mortar were totally quiet for 2 3/4 mintues before Upper Mortar started erupting (17:50:55).  Once Upper Mortar took off, Main Vent increased enough to finally hit the jugwalk.  The hailstorm stopped shortly after Fan & Mortar erupted.

The first complete pause occurred at 15 minutes into the eruption.  I don't think anyone stayed for the entire eruption because we wanted to get back and get dry clothing.  I don't remember watching a Fan & Mortar eruption in a hailstorm before and I've certainly never seen Main Vent try to start the eruption that many times.

Lynn Stephens 
 
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