Central Sierra Nevada

Despite the strong and shifting winds, larger avalanches should remain unlikely today due to the limited new snow amounts. Unlikely does not mean impossible, and some small avalanche could still occur on an isolated terrain feature, especially in an area where wind-blown snow has piled up. Watch for any signs of unstable snow and be willing to change plans if you see different conditions than expected.

Normal caution

Some small piles of wind-blown snow may have formed during the night as the SW winds pushed the fresh snow onto leeward aspects. Today E and NE winds should move that snow back across the ridges. These wind slabs should remain small, shallow, and not extend very far downslope due to the limited amount of new snow and the back-and-forth winds. This storm should not provide enough new snow to either create larger wind slabs or smooth out the uneven, wind-affected snow surfaces in near and above treeline terrain. Larger wind slab avalanches will remain unlikely today unless more snow falls than forecasted. 

Below the surface, older weak layers still exist (buried surface hoar and near surface facets) in some areas, but observations over the last several days have shown better bonding and strength in these layers. In many cases, the surface hoar layer has shrunk, flattened, or even disappeared. The last reported avalanche activity was last Sunday. On a regional scale, this avalanche problem will remain unlikely. Today's meager amounts of new snow should not add enough weight to overload these strengthening weak layers.

Even though avalanches may be unlikely today, that does not mean they are impossible. Some isolated terrain feature could still produce an avalanche today. Keep an eye out for signs of instability, like cracks in the snow, or for unexpected conditions, like deeper new snow than forecasted. Focus on building travel plans that allow time for observations and good group discussions. This will help the group find snow and terrain that fits their goals and skills. Practice good travel techniques by moving through avalanche terrain one at a time and regrouping in safe areas away from steep terrain.  

Recent Observations:

• Soft winter snow can still be found on shaded northerly aspects in wind protected below treeline terrain.
• Melt-freeze crusts have formed on sunny slopes. These crusts should remain mostly firm and frozen today. Some roller balls or small loose wet instabilities have occurred on these slopes in the last few days.
• Strong winds have hammered open slopes exposed to the wind. Widespread uneven wind-affected snow surfaces exist on these slopes, including sastrugi, wind-sculpted snow, wind-pressed snow, and wind-scoured snow.
• The layer of surface hoar buried on Jan 29 varies widely by location in crystal size and weakness. Areas around I-80 and north seem to have the highest chance of larger buried surface hoar. Observations on Thursday at Yuba Pass showed this layer to be unreactive.