Central Sierra Nevada

General Spring Avalanche Statement

The 2025-2026 operating season has come to a close. Thank you to everyone who makes this program possible by supporting the avalanche center.

As long as a snowpack still exists, avalanche activity can still occur. Wind and new snow that come with spring storms can bring storm snow avalanche problems. On warm days, expect the snow to get wet and mushy, and watch for wet snow avalanche problems. Cornice failures and glide avalanches can also happen during the warm spring weather. Pay attention to the conditions as you travel in the backcountry and adjust your travel plans accordingly. 

The observation platform will remain active for people to share snow, weather, and avalanche observations with the community.

Keep reading for some information and resources to aid in trip planning and decision-making.

Wet Loose Avalanches:

Avalanches of wet loose snow will continue to occur this spring on all aspects and at all elevations. The amount of instability and how rapidly the instability forms will vary from day to day. When recent new snow experiences rapid warming, it will almost always be problematic.

Once the snowpack has undergone several melt-freeze cycles, wet-loose instability will depend on how much the snow refreezes at night and how quickly and how much that refreeze melts during the day.  Overnight cloud cover can prevent the snow from refreezing. The NWS-Reno Backcountry Weather Forecast can help predict cloud cover and warm temperatures. GEOS Satellite imagery shows the extent of overnight cloud cover. Check the weather station table for a list of early morning air temperatures at various locations around the forecast area. On nights with cloud cover and above-freezing air temperatures, expect little to no overnight refreeze. It's best to avoid avalanche terrain on the days that follow those warm, cloudy nights.

If the sky is clear overnight, enough heat can escape from the snowpack into the night sky to refreeze the top several inches of snow. This process is called radiational cooling, and it can cause refreezing even when overnight temperatures are 5 to 10 °F above freezing. These superficial refreezes usually allow for short periods of supportable snow in the morning. These refreezes are often weak to nonexistent in areas where tree cover exists. Comparing how thick the surface crust is on open slopes vs slopes under thick forest canopy will indicate the overall strength of snow surface refreeze. The further and longer air temperatures drop below freezing overnight, the stronger the snow surface refreeze.

As the days warm up, those refreezes will melt. Once the surface crust becomes weak, punchy, or unsupportable and the snow starts to feel wet and mushy, wet loose avalanches are possible. Roller balls, pinwheels, and sinking into deep, wet snow when you step off your equipment are all clues that enough wet snow exists for wet loose avalanches. Traveling on less-steep terrain is one way to enjoy soft, wet snow and reduce exposure to this problem. Another way is to time your travel so you exit avalanche terrain before the snow gets too mushy and wet. 

New snow avalanches (Storm Slabs and Wind Slabs):

Expect a period of snowpack instability during and immediately after spring storms, followed by a second cycle of avalanche activity when rapid warming occurs after the storm clears.

Spring storms often deposit new snow on top of melt-freeze crust. If enough snow accumulates during these spring storms to form a cohesive slab, avalanches could occur in both sheltered and wind-loaded areas. Recent avalanches, snowpack collapses, audible whumpfing sounds, shooting cracks, blowing and drifting snow, and feeling more dense snow on top of softer snow can indicate that unstable slabs exist. During the storm, approach avalanche conditions as you would mid-winter.

Post-storm, expect rapid warming to increase instability. New snow will be very sensitive to rapid warming and incoming solar radiation. Newly formed wind slabs and storm slabs are often easier to trigger post-storm during rapid warming.

Glide Crack Avalanches:

In areas where the snowpack rests on smooth ground, such as granite slabs, glide cracks can open as the snowpack creeps downhill. Sometimes these glide cracks release as glide avalanches, and sometimes they don't. Glide avalanches can happen seconds after a glide crack opens or months after the crack forms. Predicting when a glide crack will avalanche is virtually impossible. Avoiding travel on or below slopes with glide cracks represents the best plan to deal with glide avalanches due to their uncertainty and potential size.

OBSERVATIONS

Daily forecasts have ended, but you can still post observations to share avalanche, snowpack, and weather information with the community. Here is a page about submitting observations.

Submit Observations:

• Click Here to Submit an Observation
• Submit an Observation with the Avy App: Apple | Android

View Observations:

• CLICK HERE to view Observations.
• CLICK HERE for details on recent Avalanches.

WEATHER LINKS:

Check the NWS Reno Backcountry Weather Forecast page. 

Check on the Weather Station map and table pages for info from additional specific weather stations.

Use the GEOS satellite imagery for assessing overnight cloud cover

Other Information:

Researchers Ian McCammon and Sara Boilen are developing new tools to help backcountry skiers and boarders manage human factors. This survey asks about personal experiences with human factors and will take 7-8 minutes to complete. Link is HERE. Thank you for your help!