The Avalanche Review, VOL. 8, NO. 4, FEBRUARY 1990
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Avalanche Evaluation Check List

by Scott M. Kruse

The original source for this Avalanche Evaluation Check List is Martinelli (1978). Pete Martinelli intended the checklist to serve as a reminder of the important things to look for in avalanche terrain and as an objective way for nordic skiers and mountaineering clubs to gather data on regularly scheduled tours.

I revised Martinelli's checklist using MacDraw II and my Macintosh computer. The checklist is a valuable tool for clearly communicating avalanche potentials to scouting groups, individuals participating in weekend nordic ski outings, highway maintenance personnel, resource management professionals, and avalanche safety personnel.

The checklist is simplistic, but helps the user notice avalanche signs and symptoms that would otherwise be overlooked. When used in combination with a current USDI-Geological Survey 1:24,000 (7.5') topographic map, characteristics such as slope gradient, starting zone and track size of an avalanche slope readily "come alive" for the observer.

To be used effectively, the checklist should be filled out at least two times for a specific slope: once in mid-summer and once in mid-winter. Additionally, topographic slope profiles should be prepared in combination with photographs to delineate starting zones, tracks, and runout zones. Visits to a site should include looking up from the bottom, down from the top, and across each avalanche path. Summer and winter aerial photographs if available are helpful. The resulting data does not provide an objective score or rating for an avalanche path, only an indication of avalanche potential.

I have used this checklist effectively with a wide variety of professional and lay groups in the Sierra Nevada and Rocky Mountains and found a very positive response. Boy scouts working on a nordic skiing merit badge and professional geographers are quickly brought "up to snuff" by using the checklist. The aesthetically-pleasing mountain slope that people have driven or skied past for several years becomes a very-hard-to-ignore potentially dangerous avalanche zone.

I usually supplement the "Part IV. Snow Depths and Climatic Data" section of the checklist with more detailed climatic information. In California several sources of snow and climatic data are readily available: alpine and nordic ski area records, specific snow course information from the California Snow Survey Measurement Schedule, utility company snow course and snow sensor records, and climatic data for the most recent30-year period from the National Climatic Data Center. Specific snow course and snow sensor data, frequently dating back to 1930, can be downloaded via modem from the California Data Exchange Center (CDEC) in Sacramento, California.

When used in combination with the Twelve Contributory Avalanche Factors (old snow depth, old snow surface, new snow depth, new snow type, density, snowfall intensity, precipitation intensity, settlement, wind direction and wind speed, temperature, subsurface snow crystal structure, and tidal effect), the Avalanche Evaluation Check List is a cost-effective tool for identifying the location, size, and extent of alpine ski area, highway, and backcountry avalanche zones.

References

California Data Exchange Center (CDEC) (1989). Sacramento, CA: Department of Water Resources.

Martinelli, M., Jr. (1978). Recognizing Avalanche Paths. Off Belay 42 (December): 2-9.

Pardee, J., G. Hester, F. Gehrke, & D. Hart (1989). 1989 California Snow Survey Measurement Schedule. Sacramento, CA: State of California, The Resources Agency, California Cooperative Snow Surveys, Department of Water Resources.

USDC-NOAA-Environmental Data and Information Service (1982). Monthly normals of Temperature, Precipitation, and Heating and Cooling Degree Days 1951-80. Climatography of the United States No. 81 (California). Asheville, NC: National Climatic Data Center.

The Avalanche Review, VOL 10, NO. 6, APRIL 1992
Copyright © All Rights Reserved; AAA