Temperature
Forecast the maximum and minimum temperatures expected in the next 24 hours at or near the elevations of avalanche starting zones. Note the general day-to-day trend as well as the diurnal spread from minimum to maximum. If possible, also forecast temperatures at 3- or 6-hour intervals since it will help you:
- Analyze same-day trends
- Examine how the temperature is expected to change during a precipitation event
- Calculate new snowfall densities during a storm
You can use model temperature data for this forecast, such as:
- Model-predicted surface temperatures (2 m or 10 m above ground level)
- Forecasted temperatures on upper-level constant pressure surfaces
- Forecast soundings and time-height cross sections
You also need to forecast the snow level within mountainous terrain. You can often extract this directly from a model forecast of the height above the surface of the 32°F (0°C) wet-bulb temperature (wet bulb zero level). If not available, use this rule of thumb: the snow level will be about 300 m (1,000 feet) lower in elevation than the forecasted freezing level.