At the upper elevations strong winds and new snow continued to load leeward slopes overnight. Six inches of new snow with about a half inch of moisture accumulated in the mountains after sunset. During the past 24 hours strong west-southwest to northwest winds with average speeds of 20 to 48 and gusts to 66 miles per hour have loaded lee slopes. Snowfall totals since Saturday morning are nearly 20 inches with over 1.5 inches of moisture. Areas of unstable snow exist and human triggered avalanches are likely in very steep, wind loaded avalanches starting zones at the upper elevation and possible at the mid elevations. Natural avalanches activity is possible at the upper elevations.
Dense slab avalanches one to to three feet in depth could be human triggered or release naturally at the upper elevations. The deeper slabs are more likely to occur on northerly aspects, failing on a buried layer of faceted snow at the base of the snowpack. At the mid elevations some potential exists for humans to trigger slab avalanches up to two feet deep.
A clockwise flow of subtropical Pacific moisture will ride up and over a high pressure ridge to our west and bring another significant storm event to our region. Light snow is expected to develop and increase in intensity by 2 AM. Snow, heavy at times, will continue through the day and evening and decrease on Wednesday. Temperatures will be in the teens at elevation, when the storm begins tonight and rise into the upper 20s during the day. The snow is likely to mix with or turn to rain at the lower elevations where temperatures will rise into the 30s. West-northwest winds will increase to speeds of 20 to 30 with gusts to 40 miles per hour. Whiteout conditions are likely along exposed ridge lines. Loading from the new snow and strong winds combined with rising temperatures will be increasing the hazard during the day. The greatest hazard will be at the upper elevations in steep, wind loaded avalanche starting zones. In these areas surface slabs one to two feet in depth are likely to be human triggered and could step down to the ground on northerly aspects above an elevation of 9,000 feet. The general avalanche hazard is expected to remain CONSIDERABLE at the upper elevations. Warming temperatures and the new precipitation are expected to create a MODERATE hazard at the mid and lower elevations.
