Eastern Sierra Avalanche Forecast - 3/14/14

The backcountry is more accessible than it has been in years. Please help!  ... Click Here to Find Out How

THIS AVALANCHE ADVISORY EXPIRED ON March 15, 2014 @ 7:08 am
Avalanche Advisory published on March 14, 2014 @ 7:08 am
Issued by Sue Burak - Inyo National Forest
bottom line

The overall avalanche danger is generally LOW for the Mammoth Basin and June Mountain areas.  Even though the danger rating is LOW, small avalanches can occur in isolated areas on slopes steeper than 35 degrees. Watch for Isolated areas of fresh wind slabs today at mid slope locations where strong east winds caused eddies below the lee sides of ridges. Watch for sunny southeast facing slopes as the sun gets higher in the sky by mid day when small wet loose snow instability may occur at  mid-elevations below the alpine zones.  

How to read the advisory


  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Bottom Line

The overall avalanche danger is generally LOW for the Mammoth Basin and June Mountain areas.  Even though the danger rating is LOW, small avalanches can occur in isolated areas on slopes steeper than 35 degrees. Watch for Isolated areas of fresh wind slabs today at mid slope locations where strong east winds caused eddies below the lee sides of ridges. Watch for sunny southeast facing slopes as the sun gets higher in the sky by mid day when small wet loose snow instability may occur at  mid-elevations below the alpine zones.  

  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Wind Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small
  • Trend ?
    Decreasing Danger

Watch for fresh wind slabs along rocky ribs and cross loaded slopes in alpine terrain.  Strong east and northeast winds stripped some north facing slopes like Red Cone. Reports from the Mammoth Crest area found small senstive wind drifts in the middle of steep north facing slopes. 

Avalanche Problem 2: Loose Wet
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small
  • Trend ?
    Increasing Danger

Even though it will be warmer today than yesterday, I think wet loose snow avalanche activity will be minimal. After another few warm days and warming nights, wet snow instability will increase at the mid elevations and possibly in alpine terrain on east to southeast facing slopes.

Avalanche Problem 3: Persistent Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small
  • Trend ?
    Decreasing Danger

Finding a spot on a slope where you could trigger and deep slab avalanche on old facets and depth hoar is a low probability event, though recent reports of propagation on buried facets suggests the problem still exists. 

recent observations

The combination of brisk east and northeast winds and cool temperatures kept slopes firm and carveable in the alpine zones the last two days. Snow temperature profiles on north and northeast slopes show the upper 20-30 inches of the snowpack remains cold. A snowpit profile will be posted later today. Snow temperatures at mid elevations of 9,000 to 9,800 ft are closer to freezing.  I monitor snow temperatures and watch for surface melt penetrating the snowpack now because the multiple layers of facets and crusts are potential weaknesses where a wet snow or wet slab avalanche can occur.  A string of nights where the air temperature does not drop below 32 F is a red flag that indicates the potential for wet snow and wet slab avalanches is increasing.

CURRENT CONDITIONS Weather Observations Between June (10,000 ft.) and Mammoth (11,000 ft.)
0600 temperature: 26 deg. F.
Max. temperature in the last 24 hours: 42 deg. F.
Average wind direction during the last 24 hours: NE
Average wind speed during the last 24 hours: 45 mph
Maximum wind gust in the last 24 hours: 70 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 49 inches
weather

Morning lows are running in the upper 20's at 6 AM. Winds are from the northeast and north at the top of Mammoth Mountain. The next 3 to to 5 days will be sunny with highs in the mid to upper 40's at the 9,000 to 10,000 ft elevations. Overnight lows will be in the upper 20's. By Sunday, daytime highs will be 10 degrees above average for this time of year.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
  Friday Friday Night Saturday
Weather: sunny clear sunny
Temperatures: 40-45 deg. F. 25 deg. F. 45-50 deg. F.
Wind direction: west north north
Wind speed: 10-15 5-15 5-15
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
  Friday Friday Night Saturday
Weather: sunny clear sunny
Temperatures: 35 deg. F. 15 deg. F. 35-40 deg. F.
Wind direction: NW N N
Wind speed: 15-20 15-20 15-20
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

ESAC receives support from ...