[Geysers] End of season West Thumb report

[Ben Hoppe]

Hi all,

It was great to have the opportunity to see, meet, and in some cases
re-meet some of you this summer. Thanks to all who gave West Thumb some
extra love and attention throughout the summer. I'll pass along the final
reports of what I've observed throughout the final months of the season at
Yellowstone's most scenic geyser basin. Feel free to use the following
information in the next Sput.

*Mimulus Pools* dropped a couple feet at the end of August. Water that had
previously been a slightly murky, yet blue color turned completely muddy.
You can now make out each individual crater of the Mimulus Pools - some of
them are connected, as opposed to appearing to be one large feature early
in the season.

*Twin Geyser* continues to have no water and show no signs of having any
water any time soon. Steam is only visible on cool days or mornings.

*The central boardwalk area* (Blue Funnel, Ephedra, Perforated, Thumb,
Collapsing, Ledge, and Surging) shows even less activity now than it had a
few months previous. With the exchange of energy near the uphill part of
the basin (Mimulus Pools and surrounding area), the feature just upslope
from Thumb is now discharging a sizable amount of water into Thumb Geyser.
Thumb's water level is at least 2 feet lower than it had been through late
July/early August. Similar drops in water level have been noted in the
other features with visible water, specifically Ledge and Collapsing.

The *Thumb Paint Pots* have waxed and waned in activity throughout the
summer. One of the cones was having some lively activity last week (9/25),
but this activity remains sporadic, and nothing what the paint pots used to
be.

*Lakeside Spring* has continued to cool down. Where the runoff channel goes
under the boardwalk, I recorded temperatures of 155°F (murky water) in
June, 145°F in August (yellow thermophiles), and 138°F in September (green
thermophiles). The pool still occasionally has periods of heavier overflow,
but nothing with the intensity of overflows it had in May and June.

*Lakeshore Geyser* was one of the more enjoyable features to monitor as the
season progressed. The pressure pool became exposed and began boiling on
July 28. In the few weeks after, the main vent became exposed and had
periodic overflows. On August 29, the main vent began having observed
eruptions, we referred to them as minors as the height typically only
reached 1-3 feet. Eruptions continued throughout September, with intervals
typically ranging from 5-7 minutes. Before the eruption, water slowly rises
in main vent and pressure pool. The pressure pool is vigorously boiling
throughout the interval, sometimes to 2+ feet. As the eruption is about to
begin, the water does a quick push to heavy overflow from the main vent,
which causes the pressure pool to cease its boiling. The main vent then
will have an eruption 1-3' high, but sometimes it only reaches 6-9 inches
(and still other times, it only overflows). The eruption lasts for about 20
seconds and ends with a drop in water level, repeating the cycle.

*Fishing Cone* had a drop in water level of a few inches. Through August I
was still able to see water while standing on the boardwalk, but the side
vent on the cone now shows pulses of water causing overflow down the side.
Since I first noted the pulsing activity, the water level in Fishing Cone
seems to have abated.

*King Geyser *boiled all summer. That's it (that we know of).

*Skinny Geyser* continued having eruptions throughout the summer. The
shortest *recorded* interval this summer was 1 day, 16 hours. The duration
of eruptions is short enough, that it probably eluded many who might have
been in other parts of the basin for an eruption. Skinny cycles are
extremely varied, with overflows usually occurring between 30-50 minutes
apart, but I've seen it only be 15-20 minutes between cycles on occasion.
In these overflow, overflow is sustained for 1-2 minutes, creating a basin
of water (which quickly evaporates) in front of the cone. A couple minutes
after the overflow, small splashing begins from a reduced water level. If
this activity is vigorous enough, it can build up to an eruption. Most
often, though, it splashes away until the water disappears until the next
overflow. Good splashing usually begins 2-3 minutes after the overflow and
can continue for up to 15 minutes after the overflow. In most eruptions
that I saw, the eruption began about 5 minutes after the overflow.
Eruptions consistently have water for about 2.5-3 minutes, and then it
switches over to a small, unique steam phase for another 3-5 minutes. I
have recorded video different portions of Skinny cycles (including the
build up to an eruption and the eruption itself). I'll upload them and
share them when internet access allows me to do so.

*Abyss Pool* stayed a lovely green color on sunny days throughout the
summer.

*Occasional Geyser *was erupting about every 20-40 minutes. The interval
was directly related to the duration. Short duration (25-35 seconds)
yielded short intervals. Long duration (1.5-2 minutes) yielded long
intervals.

*Lone Pine Geyser* undoubtedly erupted throughout the year. But no
discernible pattern or consistent intervals were able to be recorded.
Needless to say, I missed Ralph and his amazing data contributions quite a
lot this summer.

Not sure if I'll be back next year, but I would certainly enjoy another
summer at West Thumb!

Ben Hoppe
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