Eastside panorama: Williamson to Split in the southern zone.
Since the last report conditions have changed significantly, due to a major spring thaw in the past week. Evening temps have been below freezing above 10,000′ and radiation has been cooling the snowpack surface as well. Transitional spring snow conditions have transformed to Sierra corn and skiing has been excellent on most sun-exposed slopes with enough snow to ski, above 9500′, and without forest cover. Slopes that have yet to completely transform are above 11,000′ on the steepest of due North facing slopes and above 12,000′ on a slightly broader range of N-NE aspects, but these are still skiing fairly well due to earlier wind pressing from a NE flow. We have found snow on shaded slopes below 11,500′ that are less than 40 degrees to be skiing well by mid-day when the surface crust has softened, but down below 10,000′ on Northerly aspects you may find sticky snow conditions that no wax will seem to want to glide smoothly on.
As for timing, with nighttime freezing, warm daytime temps clear to partly cloudy skies, and light winds, expect the corn to be perfectly ripe for harvest on S-SE slopes, at 9500′-12,000′, between 9:30 and 11:00 am. After that, conditions may deteriorate in quality and the risk of wet loose snow avalanches and small wet slabs in steep shallow areas will increase. Reference the Eastern Sierra Avalanche bulletin for current information on regional avalanche danger in the Mammoth Lakes area.
In summary, skiing is very good right now on sunny days after a good nighttime freeze. Light to moderate winds can extend the duration of good skiing. Down low, the snow is disappearing quickly. This will make some places no longer ideal for ski touring, but will open up some roads and access to others. We are entering the sweet spot for the spring backcountry season in terms of coverage and quality. With unsettled weather and cooling temps in the forecast for this week, as well as a possible spring storm on the way for 3rd week in April, expect the spring ski season to be ideal through the first week or two of May. Any good skiing and touring beyond that would be a nice bonus, but don’t count on it. Enjoy it out there and be safe! ~ Howie