A change in the weather is forecasted for Monday night when winter will reassert itself through the upcoming week with unsettled conditions dominating with a series of winter-like storms moving through the region bring cooler temperatures and moderate snowfalls. The new snow will be fairly warm and likely bond relatively well to the old snow surface but moderate to strong Southwesterly ridgetop winds Monday night thru Tuesday (30 to 50 mph, gusts up to 95 mph) will form sensitive Wind Slabs throughout the region on NW-N-NE-E-SE aspects. Due to the strong gusty winds and localized wind channeling, Wind Slabs may be encountered on unusual aspects, in normally sheltered areas, as well as further down slope than usual.
During the past two weeks spring has made a brief appearance with above average temperatures and for the most part sunny skies. The last snowfall recorded in the region was on March 5th with up to 7” primarily in the June and Mammoth basins, which was followed by strong winds, producing highly wind-effected and firm snow conditions in the upper elevations. Prior to this temperatures were slightly cooler than seasonable with a winter like snowpack with semi-regular snowfalls. As temperatures began to climb into the 40’s and 50’s (in paces low 60’s) the snow began to transition to a spring snowpack with melt freeze crusts forming at the surface and the snowpack as a whole consolidating and strengthening. With the arrival of Spring’s warming temperatures, Loose Wet avalanches became the dominant problem for the past two weeks. Loose Wet avalanches were observed in the Low to Mid elevations, slowly creeping into the upper elevations as temperatures continued to climb into unseasonably warm territory this last week. During the warm-up, solar aspects saw a significant loss of snowcover with some slopes becoming completely bare below ~8000’. Creeks below ~8500’ have begun to reemerge from the melting snowpack. The deep snow cover has created some rather big drops to the creek bed below creating a new backcountry hazard to be aware while approach streams and creeks.
Monday - Slide For Life conditions may exist on slopes before they thaw or areas with hard smooth wind board. Crampons, ice axes, whippets, may be required to travel safely in steeper terrain.
Cornice Warning – Cornices can fail unexpectedly, give them wide berth while traveling along ridgelines, avoid corniced slopes.
Sunday High / Overnight Low Air Temperatures in Degrees F as of 0600;
Virginia Lakes (9300’): 32 50
Ellery Lake (9545’): 33 47
Agnew Pass (9450’): 35 51
June Mtn Wx Plot (9220’): 36 49
Sesame Snow Study (9014’): 35 49
Rock Creek (9700’): 23 48
South Lake (9600’): 35 50