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Shooting cracks and small wind slabs easily triggered above treeline

Easily triggered shooting cracks along a small test slope above treeline on Mt Shasta, east facing, 8200 feet
Location Name: 
Old Ski Bowl
Region: 
Mt. Shasta
Date and time of observation: 
Sat, 02/16/2019 - 2:30pm
Observation made by: 
Forecaster
Red Flags:
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain

Location Map

96067 Mount Shasta , CA
United States
41° 21' 49.5144" N, 122° 11' 45.5568" W
See map: Google Maps
California US

Snowpack Observations

Details

  • Easy to initiate shooting cracks on small test slopes above treeline, east facing, 8200 feet.
  • Small wind slabs were easily triggered on the same slopes, also east facing
  • A very large (D4) avalanche was reported from Avalanche Gulch. The slide is estimated to have occurred during the Feb 13th avalanche cycle. Initial report of debris 30+ feet deep, broken trees and with a terminus at 7,200 feet. This avalanche likely ran serveral miles and thousands of vertical feet. Potentially a historic avalanche. Official investigation tomorrow. 
  • Below treeline, southerly aspects hit by warm sun resulting in thin zipper crust
  • Near and above treeline, moderate and gusty winds out of the west/southwest were observed all day
  • New snow depths vary from 8 inches to 2 feet on top of 2/11 crust layer. New snow fist hardness
  • A lot of blowing snow observed today. Leeward drifts were DEEP. Firm snow could be quickly followed by soft, hollow drifts.

Photos

  • Easily triggered shooting cracks along a small test slope above treeline on Mt Shasta, east facing, 8200 feet
  • Wind slab, leeward easterly terrain, above treeline, slabs 1 finger hardness, 1 foot thick
  • Blowing snow along exposed ridgelines, light snow surface texture
  • Wind slab, leeward easterly terrain, above treeline, slabs 1 finger hardness, 1 foot thick
  • Blue sky for a few moments of the day. Snow showers in AM
  • Rime on exposed objects. Rime grows into the wind and in this picture, to the southwest

Weather Observations

Details

  • Snow showers in the AM with partial clearing in the PM. 
  • West/Southwest wind switching to northwest
  • cold and chilly, but felt warm below treeline during the middle of the day.
  • High temp: 21 @ 3pm - 8,000 feet

Statistics

Cloud Cover: 
75% of the sky covered by clouds
Blowing Snow: 
Yes
Precipitation: 
Snow
Accumulation rate: 
Less than 1 in. per hour
Air temperature: 
Below Freezing
Air temperature trend: 
Static
Wind Speed: 
Moderate
Wind Direction: 
West