Loose Wet
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Overnight snow surface refreeze may have been thicker/stronger in the southern half of the forecast area last night than in the northern half. Many but not all southern locations had below freezing overnight air temperatures on the peaks last night. The northern half had more widespread inversion conditions with above freezing air temperatures last night on the peaks and the colder air on the mountain valley floors. In locations where air temperatures were above freezing last night, snow surface refreeze is expected to be strongest on open slopes and weaker and/or thinner under the forest canopy.
In all areas the snow surface refreeze will be superficial with residual wet snow that did not refreeze last night below a surface crust. Where it was colder, the surface crust will be thicker. Once the surface crust is nearly or completely melted away, the wet snow on the surface will combine with the deeper residual wet snow below it. This will create potentially unstable conditions and allow for the possibility of wet loose snow avalanches. Once the surface crust starts to lose supportability, minimize risk by focusing travel on lower angle sub 30 to 35 degree slopes without steeper slopes above.
(4/9/2021) Multiple recent wet loose avalanches and some cornice fall. NE aspect terrain along ridgeline connecting Mt. Lincoln to Anderson Pk near Donner Summit, CA.