Professional Observation

Observation Details

Signs of Unstable Snow

Snow Stability

Key Points

Toured up Esha canyon and started up Esha peak, made it to about 11,300 feet before turning back as the snowpack started to feel slabby and cohesive.  On my way down, I decide to ski cut an isolated mini windloaded chute to see how reactive the new windslab may be.  The test chute produced a soft slab avalanche on a ski cut with a 4-6″ crown that ran approx. 400 feet.  Several similar results were observed during mitigation work on Mammoth Mountain the previous day (3/28).  While the snow in the slide/debris was quite low density and posed little risk in terms of burial(debris depth 1-2ft), the slide could have easily thrown a skier/rider off balance, and with cliffs and plenty of exposed rocks higher up on Esha, I was grateful to have turned back limiting my potential exposure.

• 3-5cm of new low density snow from the river crossing(7800 feet) up until about 10,000 feet
  • The snow was quickly cooked down to 1-2cm due to warming temperatures and a few short periods of sun by the time of my decent at 2pm
• 10-20cm of new snow from 10k to 11.3k feet
  • light wind effect snow staring at 10.5K and become a bit denser/wind effected as I climbed in elevation
  • Swirling light winds observed in Esha canyon with a few gusts producing some blowing snow above 10K
• Around noon was the first time the sun broke through the clouds and started to warm the new snow
• Two recent natural R1-D1 dry loose natural slides were observed on north face chutes on Esha peak that ran approx. 1200feet
  • Two other very small recent natural dry loose sluffs were also observed along some steeper terrain directly bellow the North facing cliff bans in Esha canyon around 10.5K
• Dug a quick pit on a NE aspect on Esha peak at 11K to see what was happening bellow the new snow and found some very densely packed facets under the new snow with a total snow depth of 70cm(20cm Fist hardness new).
  • The 50cm of snow bellow the new snow contained knife and pencil hardness snow and left very little concern for any possibility of an avalanche stepping down to older snow.
• Creek crossing was simple by the Magee creek pack station and approx. 800 feet of sagebrush walking was required before hitting skinable terrain.