[Geysers] Great Fountain Recovery from Wild Phase 1994

[Lynn Stephens]

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Because, most "Wild Phase" activity of Great Fountain geyser has generally occurred in the late fall, events leading up to and coming ouf of Great Fountain "Wild Phase" have seldom been documented (one major exception is the Deutch, Johns & Johns article published in the August 1994 issue of The Sput).

The 1994 activity was preceded by a 6 hour interval leading into the eruption that turned into a wild phase eruption.  Based on Scott Bryan's reports and Ralph Taylor's temperature data, the 2008 wild phase activity was also preceded by a short interval.

Coming out of the wild phase activity, I earlier posted very briefly that multiple periods of false overflow could be expected.  Ann Deutch, Janet Johns & Lew Johns published an article in the August 1994 issue of The Sput detailing information about recovery from the June 1994 (one of the exceptions to late fall occurrences of wild phase activity.)  Some of the information they provided--

Great Fountain started wild phase activity on June 13.  "By the morning on 16 June, water bursting had ceased although bursts of steam were still being observed."

Overflow did not start until sometime overnight June 17-18.

"On 18 June the overflow seemed to occur in series of episodes divided by periods when water was out of sight in the vent.  The water sizzled as it rose over the beach.  Perimeter boils were common and boils in the middle of the pool were not uncommon."

Note that someone driving by could easily be fooled into thinking that Great Fountain would probably erupt in the next half hour or so.

"The first eruption occurred at 09:41 on 20 June....The interval between eruptions was just over seven days."

Note that the periods of false overflow lasted over two days.  

"For several days eruptions occurred which were preceded by overflows punctuated with cessations of overflow....Continuous overflow, without cessation, preceded an eruption for the first time on 25 June.  Unfortunately, the overflow lasted 146 minutes."

In 1994 "false overflows" were less common than they have been in the 2000s.  Note that the first overflow not preceded by multiple false overflows lasted almost 2-1/2 hours.  Reporting "average" overflow in The Sput was infrequent prior to 1995.  In 1995 the average was 81 minutes.  

"During the first few weeks after the wild phase, overflow times prior to the eruptions have been steadily decreasing from the high of 146 minutes to 116 minutes."

Note that exceedingly long overflows continued for "the first few WEEKS after the wild phase."  

I'm not saying that what happened in 1994 will happen again in 2008, but it will be interesting to compare the 2008 recovery with the 1994 recovery.  In any case, don't be surprised if Great Fountain stays off the prediction board for awhile.

On a slightly different topic, I noted that most wild phase activity occurred in late fall.  Scott's most recent available edition says "...wild phase happened in June 1994--unusually early in the season but occurring in a year of severe drought."

This just goes to show that the geyser will do whatever it wants, whenever it wants.  I don't think June 2008 qualifies as a drought with snow pack in the Madison and Gallatin River Basins at about 175% of normal, and about 150% of normal in the Upper Yellowstone River Basin as of June 6 according to the U.S. Department of Agriculture Based on Mountain Data from NRCS SNOTEL Sites.

Lynn Stephens




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