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  “ O ver 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 larch- spruce 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 3- 5 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 Effect on Ecosystem: -Slower Moving -Less total snowpack -Occur on more gentle slopes ( 5-20 degrees ) -Lower Elevations -Heavier debris

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 ” (Lazar, Williams)  Potential to change the timing of wet avalanches and snow quality  Air Temperature

Graphs Top of AspenBase 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; hes_preprint.pdf hes_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,  Simonson, S., Fassnacht,S.R.; “ Snow Avalanche Disturbance Ecology: Examples From the San Juan Mountains, Colorado. ” American Geophysical Union, December 2008 Simonson, S.  Fagre, Daniel B., Reardon, Blase A; “ Avalanches in Glacier National Park ” Park Science; Vol. 24 No. 1, Summer P. 37