Professional Observation

Observation Details

Signs of Unstable Snow

Key Points

We were able to get a look at a variety of aspects at all three elevation bands today in the Dana Plateau / Lee Vining Canyon area. We were out of the mountains before 1 PM and so observations may be biased towards stronger snow and better stability than may have developed in the late afternoon.

• Desipte writing in the forecast that we had a weak refreeze overnight, we found strong melt-freeze snow at all elevations on our ascent.
• BTL the crust was only 10cm thick over wet snow, but even in the early afternoon northeast, east, southeast, and south slopes below 10,000′ were mostly supportable for skis.
• Crampons and an ice axe were useful on steep (> 45 degrees)  east and northeast slopes above treeline.
• Above treeline gusty north winds provided sufficient cooling to moderate the rate of warming in the alpine. Surfaces still softened enough for secure and efficient travel.
• No signs of avalanche activity in the past 48 hours and overhanging cornices were an isolated hazard.
• There is still good coverage all the way to the road in Lee Vining canyon.