Tuesday, March 13, 2012

The Timpanogos "Glacier"

Several weeks ago, one of you asked for a discussion of the Timpanogos (a.k.a. Timp) Glacier.  Well, here it is, but keep in mind I'm an atmospheric scientist, not a geophysicist.  Those of you with a stronger background in cryospheric science and glaciology, feel free to comment and add to the discussion.

The Timp Glacier is a field of semi-permanent snow located in a high, north facing cirque on Mount Timpanogos, the towering mountain that rises abruptly above the Utah Valley and Sundance Ski Area.  It has long been a favorite spot for local skiers to get summer turns, although it requires a schlep of about 3500 vertical feet just to get to its base in summer.

The Timp "Glacier" on July 30, 1949.  Credit: Ray Stewart, summitpost.org
Topo Map Source: AcmeMapper, Googlemaps
Despite the mythical name, geologists with the Utah Geologic Survey do not consider the Timpanogos Glacier to have been a glacier during historical times:
"Mount Timpanogos, the second-highest mountain in the Wasatch Range, dominates the eastern skyline of Utah Valley. During the late 1800s and early 1900s, the cirque basin below the peak of Mount Timpanogos held a permanent snowfield that has been called “Utah’s glacier” or “Timp glacier”; since then, a small snowfield commonly remains in that area throughout the year. Whether or not glacial ice was ever present in recent historical time has not been rigorously documented, but is doubtful. The site now appears to be a relict rock glacier, but ice could still be present at its core." - Biek et al. (2010)
Rock glaciers are masses of boulders and talus that contain ice buried below the surface.  The Timp glacier appears to be a small remnant of one that can be semi-permanently covered by a snow field.  The photo below shows a nearly snow free Timp Glacier in 2003.

Source: summitpost.org
I don't know of any peer reviewed publications discussing trends and fluctuations in the coverage of the Timp Glacier.  There is some discussion at summitpost.org, including photos.  Some case is made that there was a glacier before the 1930s, although I'm inclined to go with the interpretation provided by the Geologic Survey scientists above.  Perhaps others will favor a different interpretation.  Science isn't never black and white!

5 comments:

  1. Dr Jim, I believe the USGS quad maps circa early 1950 named this feature a glacier. I am looking for the old map to confirm

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    1. Yes, I think that's the case. However, the Utah Geological Survey article states "whether or not glacial ice was ever present in recent historical time has not been rigorously documented, but is doubtful." Thus, even if it is on the map, there is some doubt about it actually being a glacier. We need to find us a geologist who can shed some light on this issue!

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  2. As Utah has no active glaciers, geologists at the Utah Geological Survey mostly map relics left behind by glaciers. There is some debate among them as to what the "fresh" looking pile of rocks in the middle of the cirque represents. Consensus leans towards a relict rock glacier but an argument can be made that it is the terminal moraine (with ice at the core) of a small glacier that occupied the cirque during the Holocene. Strong evidence exists for active rock glaciers in the Uinta Range at similar aspects and elevations where more studies of glaciation occur, but even here, study is ongoing to prove that they are indeed active, and not relics.
    One of the defining characteristics of a glacier (ice or rock) is movement, and to my knowledge, no movement has been documented in the ice or rocks in the Timpanogos cirque. Interestingly, the USGS Orem 62,500 quad from 1948 does map a glacier here, but whether this was mapped based on anecdotal evidence and aerial photos, or by a glacial geologists is unknown, I suspect the former. Pictures from the early 1900s do show crevices and deeper glacier-like features. This could represent the last gasp of a small glacier that formed during the little ice age (150-500 yrs b.p.), but I'm not aware of any documented movement of this ice.

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    1. Rich-Thanks for the helpful writeup.

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  3. If you look on the Summitpost page now, you'll see that a lot of new and useful info has been added since this page was last commented on.

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