Central Sierra Nevada

While triggering an avalanche has become unlikely on a regional scale it is by no means impossible. Isolated areas of instability may exist today from previously wind drifted snow (wind slabs), deep persistent slab instability, or loose wet snow. LOW avalanche danger exists for all elevations. Travel using normal caution with a plan to step back into safer terrain if conditions warrant.

Normal caution

The snowpack has continued to gain strength since the last series of storms. The likelihood of triggering an avalanche has now reduced to the unlikely category on a regional scale. Do not confuse this with impossible as isolated instability may still exist on the slope scale.  Travel using the techniques of normal caution to minimize the consequences of an unexpected avalanche event and do not underestimate potential avalanche size or runout distance.

Winds slabs: With lighter winds yesterday, last night, and today, wind slabs that formed this past Sunday-Thursday on all aspects near and above treeline have now had a chance to bond and gain strength. A lingering small unstable wind slab is not out of the question today, but would likely be size D1. Give a little extra space around recently formed cornices and wind pillows.

Deep Persistent Slabs: Five days have passed since the last known deep slab avalanche occurred on Feb 2. In this time the old weak layers in the snowpack on NW-N-NE aspects that were heavily loaded by the Jan 26-29 storm cycle have had time to adjust to the new load and gain strength under a deeper snowpack. We suspect that this deep slab avalanche cycle has come to an end. If a deep slab avalanche were to occur today it would likely surprise the party involved and be large to very large at size D2 to D3. Remember that deep slabs are less predictable at the tail end of the cycle so do not let your guard down with lackadaisical travel techniques. Think "If this slope avalanches, it will be big" and travel accordingly especially in terms of selecting spots to regroup before or after passing through avalanche terrain.

Loose wet avalanches: Areas of surface wet snow will certainly form again today. Despite the well above freezing air temperature forecast for today, loose wet avalanches are expected to be minor at best (size D1 or roller balls only). The recent storm snow has undergone gradual warming and is getting a solid refreeze each night under clear skies. We are rapidly approaching the more critical levels of incoming solar radiation that start around Feb 15 to March 1 and progress into spring so this will become a greater problem in the coming weeks.

Recent Observations:

* Signs of wind slab and deep persistent slab avalanches from the past 11 days are visible in many locations around the forecast area.

* Wind drifting snow came to an end yesterday but was widespread over the previous 5 days. A patchwork of wind slab and wind scoured areas exists in near treeline and above treeline terrain on all aspects.

* Snowpit data has shown strength gains at all heights in the snowpack. The recent storm snow that makes up the top half to two-thirds of the snowpack has bonded well. Old deeper weak layers in the lower portion of the snowpack have significantly reduced reactivity or signs of instability in snowpit tests. These deeper layers do not gain strength at the same rate in all locations so there will continue to be isolated unstable test results that should not be ignored and maybe some of the only clues to isolated deep instability.

* Snow surface melt and overnight crust formation has occurred in the vast majority of areas. Only the most well shaded slopes at mid to upper elevations have yet to undergo snow surface melt.