Page 3 - SVHS Ops Plan 2017_18

2. OPERATIONAL STABILITY PROGRAM
The Snow Stability Forecasting Process
Management of avalanche danger depends in part on the knowledge of current snow conditions and the ability to reasonably predict snow stability (forecasting). It is a continuous process of integrating pertinent data from many available sources. Information available for analysis can be grouped into three data classes that are used for observing conditions and making forecasts:
1. Avalanche Activity
2. Snowpack Observations 3. Weather Observations
SVHS observations, combined with observations from the Sun Valley Ski Patrol (SVSP), the Sawtooth National Forest Avalanche Center (SNFAC), other local ski guide services, and backcountry skiers provide a constant stream of information from these categories. This information can be analyzed to produce an initial snow stability forecast for a particular area or zone. The initial snow stability forecast is then compared against actual conditions and observations in the field.
Meteorological Information
The primary weather variables of interest to the snow stability forecaster are precipitation, wind and temperature. Additional variables include humidity, solar radiation and barometric pressure. These variables are monitored to assess their effects on future weather, flight conditions, snow stability and avalanche potential.
SVHS analyzes weather data from many sources. The primary sources are various remote weather stations within the operating area including but not limited to those on Titus Ridge, Baldy, Vienna Mine, Dollarhide Summit, and Lost-Wood Divide. Weather forecasts, specifically the “Snow Avalanche Guidance Product” issued from the Pocatello office of the National Weather Service, and the current weather conditions are analyzed to assist in generating a proposed plan of operations for the day. During the day guides record pertinent weather observations in their field notebooks.
Snowpack Information
Investigation of the structure and stability of the snowpack can assist guides in locating potential strengths and weaknesses. Although the data is highly site specific, it can offer additional clues regarding slope stability and may be checked in the same general area periodically throughout the winter to monitor its changes. Observations and estimates of snow cover distribution, penetration depth of the snow, snowpack layering, hardness and densities of the layers, grain types and sizes, and temperature profiles are examples of snowpack information.
During field operations, guides may conduct snowpack tests in the areas they are skiing or in areas they plan to ski. Guides conduct these tests on various aspects and at different elevations to get as many samples as possible. The report of a poorly bonded layer found by a guide in the field during this ongoing testing is one factor in determining the frequency of testing that may be needed.
3
P.O Box 978 Sun Valley, ID 83353
Phone: 208.622.3108 E: info@sunvalleyheliski.com W: sunvalleyheliski.com