Yesterday morning there was 15-18” of new snow above 9,000 ft in Rock Creek, the Mammoth Lakes Basin and the June Mountain area. Winds were light during the storm and with deep new snow, the most common avalanche observations were loose snow sluffs. June Mtn ski patrol reported a few soft slabs but mostly small sluffs. There was a slab avalanche reported in Solar Bowl in the Negatives and numerous long running loose snow slides that released during the storm.
The local mountains picked up 2” of water content over the last week, adding much needed water to the large existing deficit. The 2014 snow accumulation season has ended up tied with the 2007 winter for the second driest since 1949 at Mammoth Pass. Storm totals for the last week of March range from 26” of snow with 2.4” water content at Mammoth Pass, 17-20” at the Sesame Street study plot and 20 inches at 9,600 ft in Rock Creek.
The Monday night/Tuesday storm was a powerful spring storm and created a few avalanche problems. Wind slabs will be an issue on exposed steep, upper elevation slopes. Control work on Mammoth Mountain produced some of medium sized soft slabs 12" deep.
Due to the deep amount of new snow, slopes do not need to be wind loaded in order to produce avalanches. A loose snow avalanche can carry you into rocks, trees or over cliff bands. As backcountry users it’s important to note that we are in the realm of human triggering today- there may be a lack of obvious signs of instability such as recent avalanches and cracking or whumpfing. Investigate each slope carefully before committing to steep terrain and always be thinking about the consequences of an avalanche.