Today (Sunday) – The weather forecast calls for sunny skies early, then becoming partly cloudy with high temperatures ranging from mid 20’s to low 40’s. The hard freeze last night, cool temperatures today, increasing clouds, and forecasted breezy conditions will keep the snow well frozen in most locations through the day, which will limit the concern for the wet instabilities that have been the primary concern for the past couple of weeks.
The approaching storm is another “inside slider”, which generally usher in colder air and brief light to moderate snowfalls, which will bring welcomed relief from an otherwise dry start to February. Snowfall amounts of 2”to 6” are expected over the higher elevations by Tuesday AM with moderate to strong Southwesterly winds, becoming Northeasterly late Monday. The cold dry snow will be slow to bond to the icy spring-like snow surface, increasing the potential for tender slab formation. This combination of winds, low-density snow, and icy snow surface will readily form Wind Slabs, initially on NW-NE-SE aspects near and above treeline. Late Monday, as the cold front begins to move off to the east, winds are forecasted to swing to the Northeast. These moderate winds will form a new round of Wind Slabs on NW-SW-SE aspects near and above treeline. Despite the elevated avalanche risk, this is a welcomed break in the pattern that has dominated the weather since late January (1/27). Snow coverage continues to be thin with plenty of hazards lurking below the snow surface, such as rocks, logs and stumps. The new snow will only hide the hazard while providing little protection.
Patchy persistent weaknesses continue 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 currently relatively non-reactive. The approaching cold front is forecasted to produce 2” to 6” of low-density snow. This is unlikely enough load to stress the underlying persistent weakness enough for it to become widely reactive. However, near treeline where the persistent weakness exists, there is the potential that a Wind Slab failure could trigger a larger avalanche on these deeper weaknesses.
Below ~9,000’, natural and triggered releases are unlikely due to thin and well-anchored snow coverage (below threshold).