[Geysers] Two Mastiff eruptions and one Giant eruption (Stephens)

[lynn stephens]

I made a quick trip to the Park this weekend, driving down from Bozeman Saturday morning and returning to Bozeman Sunday afternoon.
I spent most the day at Giant on Saturday, leaving after the hot period that Mike Keller and Matthew McLean have already reported.

I went to Fountain.  Fountain is having 7 plus hour intervals, with durations of 42 minutes Saturday morning (per Nancy and Robert Bower) and 35 minutes Saturday evening.  Clepsydra shut off about 6 minutes after Fountain started Saturday evening, attempted to restart 4 minutes later, then stayed off for 16 minutes after Fountain ended, for a total pause of 22 minutes.  Nancy and Robert Bower said Spasm was not erupting before the start of the morning Fountain; it was erupting prior to the start of the evening Fountain.  More than one person made a comment to me about "Fountain's long intervals and long durations."  These 7 - 8 hour intervals and 35-45 minute durations are longer than those we've had in recent years, but the ones we've had in recent years have been short.  One other note from the area--Old Cone is active.

This moring Grand was about 6:15 ie, 2 bursts, and again at 12:49ns, 2 bursts.  I think we all missed the start of Grand because we were watching Giant erupt.

I'll just give a quick rundown of the preceding events.

Grotto Fountain was at 18:11 Saturday evening, with Grotto starting at 18:30.  Grotto erupted most of the night.

This morning water levels in Mastiff and the Giant Indicator Pool were high.  Water levels seemed to be running several hours ahead of where they had been yesterday.  At about 9:15 Paul and Suzanne said the water levels looked about the same as they had about 3:30 or 4 yesterday afternoon.  I was updating prediction boards, so arrived at the Giant platform about 9:50.  Standing on the boardwalk, I could see water in Mastiff's pool at 10:07, then again at 10:24.  There was a surge from Mastiff's front vent at 10:25 and Posthole was "blipping" at 10:26.  Bijou turned on strong at 10:27, the first eruption of Bijou we had seen this morning.  Bijou turned off at 10:32.

Water was once again visible to me standing on the boardwalk at 10:47.  Feather turned on at 10:47:48 and Feather's Satellite turned on within 7-8 seconds.  Mastiff was in overflow at 10:49:33.  Mastiff started to drop and Bijou turned on at 10:51:09.  As had happened yesterday, Feather and Feather's Satellite stayed on, with Feather erupting to the height of Giant's cone most of the time.  Mastiff had dropped such that I couldn't see any water in the front pool while standing on the platform.  There were occasional "fingers" splashing up from back Mastiff.  For the next 24+ minutes, Paul would periodically announce "We're 13 1/2 minutes in and nothing's changed."  Bijou, Feather, and Feather's Sat. were the only things erupting.  There was almost no steam from the Southwest Vents or from Turtle.  20 minutes and still Bijou, Feather, and Feather's Satellite.  Then at 23 minutes the people watching the GIP said it was rising fast, Bjou turned off for about 30 seconds, the GIP 
 dropped, Feather's Sat turned off and Feather turned off.  Total duration of Feather 24 minutes 42 seconds.

Some of us waited to see how long it would take Bijou to turn off, while others started to drift away to look at other geysers.
Less than 8 minutes after Feather had turned off, Suzanne said "Bijou's off" at about the same time Paul said "Mastiff's rising.  No joke, Mastiff's rising."  Feather turned on at 11:22:00, the Satellite turned on within 15 seconds, and about 10-12 seconds later the southwest vents turned on.  This time Mastiff had periodic surging but the pool always stayed up such that water was pouring off the platform from Mastiff's overflow even when Mastiff wasn't surging.  Bijou turned on at 11:28:40 and Catfish turned on for a few seconds.  Bijou continued, but Mastiff continued to have surging.  Some one jokingly said, the third burst is the biggest, then said the fifth burst is the biggest, "I knew it was a prime number."  Mastiff was in full eruptoin at 11:31:45 with both vents 25-30 feet, pounding, and then Mastiff was 40-45 feet high.  Giant finally started showing water and erupted at 11:33.  Total duration of Giant 85 minutes.

What an opening weekend!  (Several of us were hoping for April 22 since we'd seen an eruption of Giant on opening weekend April 22, 2000, but this time we not only got Giant, we also got a solo eruption of Mastiff.)

Lynn Stephens 
 
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