Avalanches: Disaster or

Miracle?A Changing Ecological

EffectJason Blair

February 21, 2009Winter Ecology Spring 2009

Mountain Research Station, University of Colorado, Boulder

Introduction

A commom natural disaster with frequently overlooked ecological benefits.

Inherent Danger and Destuctive NatureAvalanche 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 CorridorsForest ComplexityAvalanche 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 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 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 CoverBiodiversityNew Seedling EstablishmentMore Complex and Balanced Ecosystem

Dynamics and ecology of Avalanches being directly effected by climate change.Changing CycleWetter SnowpackLess disturbance avalanches

More reasearch is necessaryFurther 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_avalanches_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