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Avalanche Advisory for 2018-04-01 06:39

  • EXPIRED ON April 2, 2018 @ 6:39 am
    Published on April 1, 2018 @ 6:39 am
  • Issued by Andrew Kiefer - Mt Shasta Avalanche Center
  • April 1, 2018 @ 6:39 am

    Advisory Hotline: (530) 926-9613

  • The avalanche danger is LOW at all elevations and NORMAL CAUTION is advised. Watch for falling rime ice and slick snow surfaces in alpine terrain on Mount Shasta. Increasing cloud cover and strong north winds may create challenging climbing conditions on the upper mountain this afternoon.

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

Avalanche Problem 1: Normal Caution

  • Character ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Generally safe avalanche conditions exist in the backcountry. LOW avalanche danger does not mean NO avalanche danger:

  • Strong solar radiation and warm temperatures¬†can cause loose wet avalanches. Travel when the snow surface is colder and stronger. Plan your trips to avoid crossing on or under very steep sunlit slopes during the peak heating hours of the day.
  • Small cornices exist on easterly aspects above treeline. They¬†may weaken and fall as the warm and sunny spring weather continues. Avoid traveling on top of or below these formations.
  • Watch for small isolated wind slabs where areas of drifting have occurred and firm layers of surface snow overlie softer layers.

Advisory Discussion

Recently, conditions on Mount Shasta have been warm, sunny and beautiful. Snow surfaces are smooth and beginning to transition to corn, and climbing season has begun. Anything is possible in the spring, though. Warm sunny days can be immediately followed by winter-like conditions that present snow and avalanche danger, extreme wind, whiteout conditions and cold temperatures. The next 24-hours may be a good example how quickly the weather can change this time of year. An incoming cold front this afternoon will bring increasing clouds, strong and gusty north winds and limited visibility. Plan to be off the upper mountain before conditions change.

Recent Observations

Yesterday, highs reached the 50s on Mount Shasta while temperatures in town hit 70 degrees. Steady NW winds blew above treeline averaging 10-15 mph with gusts to 35 mph. Between 7,000-10,000 ft on Mount Shasta, the height of snow ranges from 4-8 ft and overall, coverage is good. No avalanches or significant signs of instability have been observed in over a week. Snow surfaces remained firm above 10,000 ft on Mount Shasta, while below, a corn cycle has begun on southerly aspects. Snow surfaces are still transitioning to corn, but overall they are smooth and uniform. Unconsolidated, wet surface snow was found near and below treeline in the afternoon, and evidence of previous wet loose activity was widespread. The snowpack is melting quickly in the Pilgrim Creek Sno-Park, Castle Lake and Mount Eddy zones.

Weather and Current Conditions

Weather Summary

Expect sunny skies this morning with increasing clouds in the afternoon. Highs will reach the mid 50s at 6,000 ft. Strong north winds averaging 20-30 mph will blow above treeline. A cold front will move through the area in the afternoon bringing cloudy skies and continued north winds. Winds will reach a peak tonight on the upper mountain and then ease Monday morning.

24 Hour Weather Station Data @ 6:00 AM

Weather Station Temp (°F) Wind (mi/hr) Snow (in) Comments
Cur Min Max Avg Avg Max Gust Dir Depth New Water Equivalent Settlement
Mt. Shasta City (3540 ft) 50 37 70 55 2 NW
Sand Flat (6750 ft) station down
Ski Bowl (7600 ft) 32.5 32.5 51.5 42.5 77.5 0 0 2
Gray Butte (8000 ft) 35.5 35.5 47 41.5 14 35 NW
Castle Lake (5870 ft) 38 38 59 49 24.5 0 3
Mount Eddy (6509 ft) 35 32 53.5 41.5 2 10 WSW 42.5 3
Ash Creek Bowl (7250 ft) station down
Ash Creek Ridge (7895 ft) station down

Two Day Mountain Weather Forecast

Produced in partnership with the Medford NWS

For 7000 ft to 9000 ft
  Sunday Sunday Night Monday
Weather Sunny Partly cloudy. 20% chance of rain and snow after midnight. Partly sunny
Temperature (°F) 47 23 39
Wind Direction NW NW N
Wind Speed (mi/hr) 0-5 10-15 5-10
Expected Snowfall (in) 0 0 0
For 9000 ft to 11000 ft
  Sunday Sunday Night Monday
Weather Sunny and windy Partly cloudy. 20% chance of snow after midnight. Partly sunny and windy
Temperature (°F) 30 18 32
Wind Direction W W N
Wind Speed (mi/hr) 20-30 30-40 25-35
Expected Snowfall (in) 0 0 0

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2017 (the wet season) 15.95 35.46 45
Month to Date (since Aug 1, 2018) 5.06 5.96 85
Year to Date (since Jan 1, 2018) 10.12 20.25 50

Disclaimer

This advisory does not apply to Ski Areas or Highways and is for the Mount Shasta, Castle Lake and Mount Eddy backcountry. Use this information for guidance only. You may find different conditions in the backcountry and should travel accordingly. This advisory expires on midnight of the date it was posted unless otherwise noted.