0600 wx. at 6350′ in Carnelian Bay: 20.1° / 16.3° dew point / 84% RH / partly to mostly cloudy skies / light NW winds
Backcountry obs.:
While the second storm in this week’s series dropped meager accumulations around lake level communities, it delivered to the backcountry. Yesterday (3/6) at dawn, west shore zones along highway 89 received between 4″ at 6900′, to up to 14″ just beneath the peaks near treeline at 9100′.
The new snow rested right-side up atop saturated, refreezing melt-freeze crusts. Accumulations grew quickly with height on NE aspects. Some minor wind texture adorned surface snow, mainly at higher elevations near treeline, but with negligible effect to ski quality. However, near treeline, wind pillows on lee slopes and rollovers did react, producing shooting cracks, propagating fractures, and some minor wind slab avalanches. I observed one such skier triggered wind slab avalanche that ran like a teardrop a few hundred feet down an open E face. The slide entrained the slab and surface snow, running on a bed of firm, melt freeze crusts. No skiers were harmed.
Instability aside, the new snow skied great throughout the morning. Cold, right-side up fluff skied fast and smooth, providing long, high speed, powdery arcs on open NE faces. Down low, slower, shorter turns bottomed out on firm, pre-storm bed surfaces. However, the moist, decomposed nature of the crusts dampened any jarring contact of ski to crust providing excellent turns from summit to trailhead.
Another March morning delivered.
Weather and forecast thoughts:
This morning dawned cold under a mix of clouds and sun behind the departing storm system. Today a brisk NE flow will bring gusty winds and cold temps to the backcountry. While the cold temps. will help preserve the snow from the intense sun, brisk winds may strip new snow from near and above treeline on N and E facing aspects. Highs today will largely remain in the 20s above 7000′.
Tonight a ridge of high pressure begins to move into the region moderating winds, temps., and clearing skies. Lows tonight will drop into the teens under clear skies and slackening winds, setting the stage for a mild and sunny weekend.
The main headline this weekend (3/8-9) is the return of Sierra spring: warming temps. and sunny skies. After a cold start on Sat., temps will warm into the middle to upper 30s across the backcountry under sunny skies with light winds. Rinse and repeat for Sun. Lows both Sat. and Sun. night will drop well into the 20s with inversions looking likely each night.
Spring-like weather holds on for Mon. and Tues. (3/10-11) with mild temps. in the 30s to low 40s above 7000′. Clouds will be on the increase Mon. as a system impacts SoCal, but largely misses the Sierra. Tues. winds and clouds should increase ahead of another more impactful winter storm taking aim on the Sierra.
By early Weds., a significant winter storm looks likely to begin impacting the Tahoe Sierra through early morning Fri. Most models and ensembles show a high probability for 1-2′ of new snow at lake level, with considerably more (2-3′) into backcountry zones across Tahoe. Snow levels are also trending lower, remaining below 6000′ for the entire event. This storm has been showing up in models for the past week, which does tend to boost confidence, however it’s still at least five days and much can change as the details come into greater focus.
Beyond the mid-week storm, long term forecasts show more systems impacting the region with temps. remaining below average. CPC models show below average temps and above average precip. impacting the Sierra through the third week of March.