Solar Aspects – The high pressure that has remained parked off the coast of California is forecasted to retrograde to the west somewhat allowing weak “slider” storms to drop into the Great Basin from the north with the potential for light snowfall Monday/Tuesday. In the mean time, this will tighten the pressure gradient over the Sierras, resulting in windy conditions as cooler air moves into the forecast region. This is a welcomed break in the pattern that has dominated the weather since late January (1/27). Overnight temperatures were once again quite mild with few locations report bellowing freezing temps. However, the cooler air mass moving into the region combined with moderate to strong West to Northeast winds will slow the normal thawing somewhat but isolated wet instabilities on solar aspects (E-S-W) are possible. With the limited snow coverage on southerly aspects, Loose Wet activity will be isolated to terrain that continues to retain sufficient snow, especially east to southeast facing gullies and cirques. Exposed rocky terrain features can introduce tremendous amounts of heat into the snowpack causing rapid localized thawing. Time your travels to be out of steep sunny terrain before the snow thaws excessively is key to avoiding wet instabilities. Snow coverage continues to be thin with plenty of hazards lurking below the snow surface, such as rocks, logs and stumps.
Caution – On southerly aspects, possible Slide for Life conditions in the AM or as slopes begin to refreeze. A minor slide into hazardous terrain can have serious consequences. Crampons and Ice Axe recommended in exposed terrain.
Northerly aspects - Patchy persistent weakness continues to dwell within the snowpack with weak faceted sugar layers down about ~30 to ~60cm (12” to 24”) from the surface in most locations. Distribution is primarily confined to NE-N-NW aspects above ~9500’. Recent test results continue to show the potential for failure but relatively non-reactive. The northerly aspects remain somewhat cool but are showing signs of warming with the surface snow in mid-elevations warming and developing a melt/freeze crust. The crust maturity depends on solar exposure, duration, steepness, and shading. The snow is still somewhat soft in sheltered areas near treeline but the aspect window has narrowed to N to NE aspects and shading is key. Near treeline, where the persistent weakness exists, there is the potential to encounter small isolated older Wind Slabs that were deposited over facets in steep terrain, which could fail if a sufficient trigger is applied.
Below ~9,000’, natural and triggered releases are unlikely due to thin and well-anchored snow coverage (below threshold).
