Part of the proposed expansion of ski facilities at Crested Butte Mountain Resort,
Gunnison County, Colorado, is in an area underlain by landslide deposits
that are on the southeast side of Snodgrass Mountain. Except for localized
movement, the landslides do not appear to be moving at present or to
have moved in the past several decades. Shallow sliding and debris flows
have occurred in similar materials nearby and are likely to occur in
the landslide deposits during the 50-100 year life of the proposed facilities.
Hazards related to debris flow, shallow slumping, and expansive soils
in the deposits can be reduced by appropriate engineering and remedial
measures but maintenance for the proposed facility may become costly.
Snow making is likely to aggravate the hazards of shallow slumping, deep-seated
sliding, and debris flow. Reactivation and deep-seated movement of a
1.6-million-m3 slide at the east side of the deposits would damage or destroy a proposed gondola,
ski lift N-3, and related facilities. Moving the gondola and lift off
the slide and prohibiting snow making on the slide will protect the gondola
and lift and reduce the chances of debris-flow damage to a proposed development
near the toe of the slide. Insufficient data are available to assess
the current or future stability of the landslides or to evaluate possible
mitigation strategies; detailed stability analyses are needed before
developing any facilities on the landslide deposits.
Version 1.0
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Posted October 2005
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