Geoscience Reference
In-Depth Information
ice can flow more quickly or meltwater can act as a lubricant and reduce friction
between internal shear planes (Bucki and Echelmeyer
2004
; Krainer and Mostler
2006
; Ikeda et al.
2008
). Rock glaciers will often show an overall surface thin-
ning because of warming. Some small-scale ridge advection or heaving may be
observed; advancing ice may cause compression or overthrusting near the toe (Kääb
and Weber
2004
; Chueca and Julian
2005
; Janke
2005a
; Kellerer-Pirklbauer et al.
2008
). A variety of geomorphic (internal structure, underlying topography, slope,
curvature, etc.) and environmental (snowfall totals, snowmelt timing, temperature
change, etc.) variables must be taken into account to properly evaluate the response
of a rock glacier to climatic fluctuations.
Climate change will affect high mountain systems by altering geomorphic pro-
cesses. The increased frequency and magnitude of hazardous events in mountains,
such as glacial lake outburst floods or mass movements, such slumps, flows, rock-
falls, or others from melting ground ice, will have an economic and ecological
impact on the alpine environment (Huggel et al.
2002
; Quincey et al.
2005
; Thies
et al.
2007
). In addition, previously unaccounted sources of carbon dioxide and
methane could enhance warming as storage sinks in permafrost are released and
create a positive feedback that will accentuate hazardous events in mountains.
Remotely sensed and Geographic Information Systems (GIS) data and software
provide the proper spatial resolution, spatial coverage, temporal resolution as well
as robust operations to assess and manage hazardous events in mountains (Shroder
and Bishop
1998
; Giardino et al.
2004
; Roessner et al.
2005
; Saha et al.
2005
;
Kääb
2008
). This paper provides a case study, utilizing the California rock glacier
(37.617
◦
N, 105.486
◦
W) in southern Colorado, to illustrate the characteristics of this
rock glacier and evaluate the hazard potential in a dynamic alpine environment. A
discussion of glacial recession in the more populous Andes is also provided as an
example of how geospatial techniques can be used to increase awareness, and in
turn, develop proactive adaptive management strategies.
5.2 Study Area
California rock glacier (
≈
3655 m) occupies a portion of the Huerfano River Valley
(
3200 m) of the Sangre de Cristo Mountains of Colorado (Fig.
5.1
). Blanca Peak
(4375 m), the fourth tallest peak in Colorado, marks the southern edge of the north-
south trending Huerfano River Valley. California rock glacier is the third largest
(0.342 km
2
) of about 44 rock glaciers that cover 3.16 km
2
of the massif (Berta
1986
;Parson
1987
; Janke
2001
). The rock glacier flows in an easterly direction and
has a subdued surface slope compared to the surrounding topography (Table
5.1
). A
0.8 km longitudinal furrow meanders from the head of the rock glacier to its steep
front slope that is about 60 m high and has about a 40
◦
slope (Fig.
5.2
).
Rocks found on the surface of the rock glacier are part of the Minturn Formation
(Middle Pennsylvanian) with gray arkosic sandstone, conglomerates, siltstone,
≈
