Snowpack
View on mapLee Vining Canyon - Wind Slabs and Poor Structure
Clancy Nelson and Greg CunninghamEastside Region
Quick report
- Cracking
- specific
We got cracking in recent wind slabs in Lee Vining today. With the northwest wind causing intense blowing snow at higher elevations, we expect fresh slabs to be forming.
We found concerning snowpack structure and got propagating test results. The culprit was faceted snow around a rain crust buried on New Year's. We'll be gathering more info about this poor structure in the coming days.
Localized cracking under my skis (propagated less than 6 feet away) in recently wind-drifted snow. Cracking was isolated below treeline and specific near treeline. Cracks were breaking in facets above the New Year's Crust.Weather
- Air Temp
- Teens and 20s
- Cloud Cover
- few
- Wind Loading
- intense
- Recent Snowfall
- 10
- Snow Avail For Transport
- large amounts
It was a beautiful, mostly sunny day. Winds were light at lower elevations, though blowing snow from strong northwest winds increased throughout the day at upper elevations. There are large amounts of snow available for transport, and there was a lot more blowing snow near and above treeline south of Mammoth on the drive home.
Snowpack
- 1.5mm facets have formed above and below the Pencil hard rain crust buried 1/1.
- The overlying slab is soft and unconsolidated (F-4F) below treeline, where the layer of concern is down about a foot (35 cm), and the snow depth is around 80 cm.
- The overlying slab is 1 Finger hard drifted snow near treeline, where the crust is buried around 2 feet deep (55 cm). We got repeatable propagating test results in the facets above the crust on a northeast aspect near treeline, where the snow depth was 103 cm.
- This crust has been found on all aspects across the forecast area up to 11,000 feet. We saw this poor structure near and below treeline on northerly aspects in the northern half of the forecast area today. It's unclear where else the snow above and below the crust has faceted.