Transcript The Changing Ecological Effect of Avalanches Due to

Avalanches:
Disaster or
Miracle?
A Changing
Ecological
Effect
Jason Blair
February 21, 2009
Winter Ecology Spring 2009
Mountain Research Station, University of Colorado, Boulder
Introduction
A commom natural disaster with frequently
overlooked ecological benefits.
 Inherent Danger and Destuctive Nature
 Avalanche Corridors
Climate Change
Avalanche Path
Habitats
Avalanches not only destroy habitats, but
they create new ones.
Increase Ecotones
“The biodiversity within avalanche
tracks is highly increased compared to
the surrounding forest. The more
avalanches occur, the more significant
the difference becomes.” (Rixen)
Biodiversity
 Avalanche Corridors
 Forest Complexity
 Avalanche Cylces
 “Over 80% of the 141 observed species grew
in less than 5% of the investigated plots,
although the undisturbed vegetation outside
of the avalanche tracks consisted of a larchspruce forest throughout the entire
monitoring area” (Rixen.)
Climate Change
 “In the past 15 years the frequency of avalanches
has increased from 1 every decade to one every 35 years” (Huggel)
 Reflects changes in trigger mechanisms
 Wet Avalanches
 Permafrost
 Impermeable by meltwater
 Failing to freeze
Wet Avalanches
Danger to Humans:
-Harder to Predict
-Harder to control
with explosives
-Occur on more
gentle slopes
(5-20 degrees )
-Lower Elevations
-Heavier debris
Effect on Ecosystem:
-Slower Moving
-Less total snowpack
Aspen Mountain Research
 A 2007 study modeled climate change in CO ski
areas
 “evaluated how climate change resulting from increased
greenhouse gas emissions may affect the timing of wet
avalanches and snow quality at Aspen Mountain in the
years 2030 and 2100.”(Lazar, Williams)
 Potential to change the timing of wet avalanches and snow
quality
 Air Temperature
Graphs
Top of Aspen
Base of Aspen
Conclusion
 Avalanches are a natural disturbance like fire
 Integral part in shaping the forest community
Patterns of Forest Cover
Biodiversity
New Seedling Establishment
More Complex and Balanced Ecosystem
 Dynamics and ecology of Avalanches being directly effected by
climate change.
Changing Cycle
Wetter Snowpack
Less disturbance avalanches
 More reasearch is necessary
Further testing on how wet avalanches
effect enivronment differently.
Literature Cited

Armstrong R, Ives J.D.; “Wet snow avalanches” in “Avalanche release and snow characteristics, San
Juan Mountains, Colorado.” 1976 p. 67

Baggi, Stefano, Schweizer, Jurg; Characteristics of wet-snow avalanche activity: 20 years of
observations from a high alpine valley; November 2008;
http://www.wsl.ch/personal_homepages/schweizj/publications/Baggi_Schweizer_wet_snow_avalanch
es_preprint.pdf

Huggel, Christian; “Recent Extreme Avalanches: Triggered by Climate Change?” Eos, Vol. 89, No. 47,
P. 469; 18 November 2008

Lazar, Brian, and Williams, Mark; “Climate change in western ski areas: Potential changes in the timing
of wet avalanches and snow quality for the Aspen ski area in the years 2030 and 2100” Cold Regions
Science and Technology 51(2008) p. 219

Rixen, Christian; “Avalanches Create New Habitats for Plants” June 25, 2003
http://www.waldwissen.net/themen/naturgefahren/schnee/wsl_lawinen_pflanzen_EN?-C=&

Simonson, S., Fassnacht,S.R.; “Snow Avalanche Disturbance Ecology: Examples From the San Juan
Mountains, Colorado.” American Geophysical Union, December 2008
Fagre, Daniel B., Reardon, Blase A; “Avalanches in Glacier National Park”
Park Science; Vol. 24 No. 1, Summer 2006. P. 37
www.nrmsc.usgs.gov/files/norock/products/GCC/ParkScience_WMI_Reardon_06.pdf
