Eastside Region

Time your day to be away from steep slopes, start zones, and the runouts of avalanche paths as the upper snowpack thaws and becomes wet. Surface melt will occur earlier this morning than it did Thursday. Small sluffs coming from rocky areas, or your boots sinking deeply into mushy snow are warning signs that wet snow avalanches are becoming likely. 

Yesterday we received the first report of a wet slab avalanche within the forecast area. Dog-sledders near Aspendell shared photos of loose wet debris that triggered a slab avalanche lower down on a west-facing slope. It is worth bearing in mind that with continued warming, slab avalanches may occur. These are more likely at the southern and northern ends of the forecast area and further from the Sierra Crest where meltwater is pooling and saturating soft layers of snow above buried crusts. Several new wet loose avalanches ranging from size 1 to 2 released on north and west aspects near and below treeline yesterday. 

Snow surface temperatures at weather stations are showing a strong refreeze overnight, and air temperatures are forecast to be warmer today. That means warming will be more rapid and you will have less time before wet snow becomes unstable. Below the surface, the snowpack at lower elevations has stayed wet, and weather station data suggests that water may be percolating down through the snowpack.

Other Springtime hazards exist within warming terrain. Large cornices perched overhead deserve a wide berth. Slopes under glide cracks are places to avoid. Gabrielle Antonioli gave us a good acronym to remember the factors that come into play with wet snow instability: WUTANG. Wet, Unconsolidated, Terrain, Aspect, Not refrozen, Glide. Check out her presentation in the video below.