Valanga

Mammoth lakes basin - New snow and dry loose avalanches

Steve MaceEastside Region
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Quick report

We ventured into the lakes basin today to survey new snow totals and to evaluate surface instabilities.

  • We observed up to 70 cm of new low-density snow with ski pen around 50 cm.
  • We chose to stick to low-angle slopes and were careful to avoid terrain traps, and at times, it felt uphill in both directions.
  • We noted touchy dry loose activity on any slope steep enough to slide 
  • We observed surprisingly light winds and minimal signs of unstable wind deposits. We noted significant wind transport in other nearby areas, such as the Sherwin ridge, and increasing winds as we descended at around 3 pm. 
Storm instabilities were top of mind for us today. Surprisingly, light winds were observed, and while we did find some areas of fresh drifting and some recent cornice growth, we did not observe significant signs of wind slab instabilities in this location. However, it is worth noting that a large amount of low-density snow is available for transport, and it won't take a significant increase in speed to move it around.

Weather

Air Temp
below freezing
Cloud Cover
overcast
Wind Loading
moderate
Recent Snowfall
70
Snow Avail For Transport
large amounts

Skies remained overcast, and light snow showers continued throughout the day with occasional periods of more intense snowfall. Winds were lighter than we expected near and above treeline where we were near the crest with only light amounts of wind transport noted. However, we did witness areas with more intense loading in nearby locations and winds were increasing as we made our exit around 3 pm. Temperatures remained well below freezing.

Avalanche

Several natural dry loose sluffs were observed on steep slopes at all elevations. We triggered many sensitive surface sluffs on steep test slopes. I would call these touchy and widespread.