Eastern Sierra Avalanche Advisory 12/19/2025

An atmospheric river is set to impact the forecast area beginning today. This powerful storm is bringing a mix of intense winds, mountain snow, and valley rain. Impacts will be greater in the northern portion of our forecast zone. Uncertainty is high regarding the freezing level of this incoming storm. We will likely see rain at mid and upper elevations early in the storm, with snowlines dropping after Sunday. The addition of any form of precipitation to our weak snowpack will result in increasingly hazardous avalanche conditions.

Our current snowpack is made up of a variety of facet and crust combinations. Clear and calm weather, along with periods of strong winds, have built sun crusts and wind boards overlaying weak, decomposing snow. This general setup is present at all elevations, but unseasonably warm temperatures have made the coverage less consistent below 10,000′. At lower elevations, snow is patchy across the terrain or completely absent. Above 10,000′, coverage is more uniform. Locations holding onto more of their old snow will be the most hazardous as we move into a week of wind, rain, and snow.

In our below treeline elevations, rain is expected. Loose wet avalanches may become more likely in steep terrain where this rain is saturating the old snowpack. This will only be problematic if you’re travelling in and below places still holding onto old snow. Keep in mind, pinwheels and rollerballs are strong signals that the snowpack is saturated and cohesionless and that loose wet activity is becoming more likely.

As we move up in elevation, things get a bit trickier. Hazard will rise rapidly as the storm moves in. In places where it is raining, loose wet avalanches may be possible. In places where it’s snowing, a new slab will begin to build over weak snow. At higher elevations, we are likely to see more snowfall than rain, accompanied by strong winds. As new snow accumulates, strong winds will build new slabs rapidly on leeward slopes. Expect the size and sensitivity of avalanches to increase as the storm continues. Surface clues, such as blowing snow and recent drifting, can clue you into areas of concern. Avalanche hazard will peak during and immediately after the stormy period.

The ESAC team is monitoring this storm closely and will begin daily forecasts as soon as conditions allow.

Full Forecast ➝

This information is provided by the Eastern Sierra Avalanche Center and describes general backcountry avalanche hazard and conditions. It does not apply to ski areas and highways where avalanche mitigation is conducted.