Avalanche forecasting begins with a good understanding of past weather, from the very beginning of the “winter” season when the first snow stays put in the mountains.

If you’re in a formal avalanche forecasting situation and will be forecasting for, say, a highway department, ski area, or helicopter skiing operation, ideally you’ll want the full complement of daily historical weather data from the start of the winter season. This includes:

• Precipitation (daily snowfall and its water content or SWE)
• Maximum and minimum temperatures at forecast-area elevations
• Winds near ridge-top level or at all forecast-area elevations
• Average cloud cover each day over the forecast area

In this section you can check the historical weather observations recording from relevant automated weather sites in ski resorts and huts. This data is collected every 15 mins. Please be aware that those recordings provide a local snapshot of the conditions at this particular location and as such should not be accepted as indicative of the weather patterns in all the mountain as weather is affected by local topography and micro climates.

Recent Avalanches

Keep a record of any reported avalanches, identifying the elevation, aspect, and relative size of each event. Recent avalanche activity is one of the best indicators of an unstable snowpack. Look for clues of recent avalanche activity:

• Debris piles at the bottom of slopes
• Recent crown lines
• Newly damaged trees in avalanche paths

Look for Recent Avalanche Activity in our Mountain Report Section

Current weather

Once you’ve gathered pre-forecast information, you’re ready to evaluate the current weather situation, looking at conditions during the preceding 24 hours. Specifically, You’ll examine weather variables that have the greatest impact on snowpack and avalanche potential (precipitation, wind, temperature, and cloud cover) and determine if they’ve exceeded critical thresholds. Solar radiation is also important but will be considered in combination with cloud cover. This video guide summarizes the important weather parameters and shows how to interpret the values for avalanche potential.