[Geysers] GIANT 9/29/05 07:40 (Stephens)

lynn stephens lstephens.eagle at mail.sisna.com
Thu Sep 29 11:33:35 PDT 2005


Events leading up to the September 29 eruption of Giant:

Grotto marathoned on Monday, September 26, starting at 14:00, and Tuesday, September 27, ending about 17:00.  I started observing Giant about 0650 on Wednesday, September 28.  Giant was having some vertical splashing, but only up to the lip of the cone.  At 08:08 there was a Giant hot period with a duration of 8 minutes 35 seconds.  There was some Mastiff surging about half the height of Giant’s cone and all of India was covered. 

Grotto Fountain was ie at 13:06 and Grotto started at 13:15 (ended at 16:05).  There was a Giant hot period at 13:32 with a duration of 9m07s.  (Giant was not under observation from about 8:40 until 13:20.)  Giant continued having period vertical splashing 1-2 feet above the lip of the cone until it had a 2m25s hot period at 1627.  I stayed until 1745 because Giant was still having period vertical splashing.

Chase Ellison called a hot period at 1921 with a duration of 7m50s.  He was impressed by the amount of water that Giant was splashing outside the cone during the hot period.

When I arrived this morning (9/29) at 6:40, Grotto was in eruption.  Bijou was active until it had a short pause at 7:11.  The next pause started at 7:26.  Standing on the platform itself, I could see water in Mastiff at 7:28.  The southwest vents started at 7:29:00.  Feather started at 7:29:44.  It was a slow start.  Feather was only about half the height of Giant’s cone.  Feather’s Satellite didn’t join in until 7:32:30.  Mastiff had dropped below overflow, but then recovered.  At 4 minutes in, I noted that Cave was bubbling 4-6 inches high.  This was the first time Cave had been reported in any of the hot periods since Giant’s last eruption.  Cave never did get any higher.

At 6 minutes in the platform was steamy, but I noted India was completely covered.  Mastiff appeared to be surging about 2/3 the height of Giant’s cone.  (It was cold and steamy this morning.)

At 7:38:14 it looked like Feather and Feather’s Satellite were off.  Bijou was erupting, but Catfish was not.  But at 7:38:40 I could clearly see that both were on and Mastiff was surging again.  At 7:39 water was pouring off the platform, Giant was filling its cone and the Giant sign had washed off its perch, but Giant had not yet started.  Mastiff surged to about the top of Giant’s cone, but no higher.  Giant filled the cone one or two additional times, then I could see Giant 10-20-30-40 feet above the cone and Giant was erupting at 7:40.

After Giant started, Bijou went into a roaring steam phase.  Catfish never did erupt.  I have no idea how tall Giant’s eruption was because the water was mostly obscured by the steam.  The top of the steam cloud was golden in the sun, and some of the water droplets in the spikes were also golden.  When the “rain” came down, it turned to ice on my jacket and slush on the jugwalk.

I had been quite calm while I was calling the hot period, but was so excited when Giant actually erupted that I just yelled “Giant is erupting” into the radio, and apparently forgot to give the time.  I immediately put my radio away so I could watch the eruption.  (No pictures—although the sky was blue and the sun was shining, it was just too steamy.)  Dave Leeking was at Tardy when Giant started and heard the VC ask for the start time but he said he was looking at the steam cloud and forgot to look at his watch.  I did look at my watch for the start time—07:40.

Grotto was still erupting when the hot period started, but stopped sometime before 8:35.

The last splash of water out of Giant’s cone was at 09:20, a duration of 100 minutes.  

The Giant sign was washed off its perch, but did not wash under the boardwalk.  The Stay on Walk sign was washed a few feet, but the Bijou, Catfish and Mastiff signs were not moved by water from the eruption.

Other geyser news—Beehive continues to erupt once a day.  The last few eruptions were:

9/25 09:30 (Indicator 09:16)
9/26 10:49 (Indicator 10:45)  The Close to Cone Indicator was bubbling during Beehive’s 
9/27 07:52 (Indicator 07:45ns)
9/28 11:46 (Indicator 11:32)
9/29 10:38 (Indicator 10:28ie)

Great Fountain has been about 5 in the evening for the past few days (16:55 on 9/25, 16:39 on 9/26 per Mike Lang, 16:55 on 9/27 with a superb 150+ foot first burst, 17:13 on 9/28 per Dick Powell).  

The weather was sunny on Monday, cloudy with rain on Tuesday, sunny on Wednesday and sunny again today.  It has been warm enough that I’ve been in my shirt sleeves and shorts yesterday and today.

And, Fan & Mortar have still not erupted.

Lynn Stephens
SISNA...more service, less money.

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