Forest Floor Objects as Avalanche Triggers Andrew Benton February 23, 2013 Winter Ecology Mountain Research Station University of Colorado at Boulder Andrew Benton February 23, 2013 Winter Ecology Mountain Research Station University of Colorado at Boulder

Energy transfer from forest floor objects to the snow pack can have diverse effects depending on the object. Question: What type of forest floor object has the most negative effect, in terms of avalanche danger, on the surrounding snow pack? Hypothesis: Forest floor objects in greater contact with the soil structure will transfer latent heat to the snow pack at a greater rate. These objects will have a greater width of faceted snow surrounding them. Latent Heat Depth Hoar = Danger!

Better Understanding… eWinter Environments -Knowledge is power -Knowing the signs eSpecific to Colorado -Backcountry, to ski areas -Forest Environments

Why Study? eEducation = Prevention ePersonal Safety eSpotting the biggest hazard areas Snow surface Rock Rock Rock

Further Enlightenment! “The best strategy for survival is to avoid becoming caught in an avalanche. Avalanches can be avoided by understanding where they occur, choosing routes carefully, watching for contributing factors, and practicing good judgment (Halfpenny, Ozanne 214).” +Terrain Factors “Avalanches can begin on slopes with many anchors and anchors may serve as points that weaken the snow pack. The fracture line of slab avalanches occasionally connects between trees and rocks (Halfpenny, Ozanne 215).”

Methods eIdentifying the site areas dLogs, rocks and vegetation dMore open areas eSnow Pits dShape and precision dEffected layer eMeasurements dSnow properties, Temperature, canopy density and force to collapse eInterpretation dGeneral force trends dFacet and pore size

Results eWidth of effected layer vs. Force(kg/m^2) to collapse eTotal snow depth vs. Force(kg/m^2) to collapse ePore size vs. Force(kg/m^2) to collapse eFacet size vs. Force(kg/m^2) to collapse eLooking at what factors are the leading contributors to collapsing the snow pack.

Width of effected layer Vs. Force required to collapse effected layer Log Rock Veg. Log Veg. Rock P-Value= P-Value=0.001

Total depth of snow pack vs. Force required to collapse effected layer Rock Log Veg. P-Value=0.05 P-Value=0.02

Pore size vs. Force(kg/m^2) to collapse effected layer Rock Log Veg. P-Value=0.002 P-Value=0.001

Facet size vs. Force(kg/m^2) to collapse effected layer Log Rock Veg. P-Value= P-Value=0.009

Discussion eGeneral differences dRock vs vegetation zones eRelation of rocks to the soil dConstant heat eLogs, their airy truth *ERROR*

Works Cited ehttp:// United States search and Rescue Task Force eHalfpenny, James and Ozanne Roy. Winter: An Ecological Handbook Johnson Books. eMarchand, Peter. Life in the Cold University Press of New England.