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Avalanche Forecast for 2019-04-04 06:30

  • EXPIRED ON April 5, 2019 @ 6:30 am
    Published on April 4, 2019 @ 6:30 am
  • Issued by Aaron Beverly - Mount Shasta Avalanche Center

Avalanche danger will increase late tonight near and above treeline as 4-11 inches of snow combine with southerly winds to create wind slabs. Human triggered avalanches will be possible on steep leeward slopes.

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

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

Avalanche Problem 1: Wind Slab

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Concern for wind slab avalanches will increase tonight with 4-11 inches of new snow expected above 6,000 ft. Most of this snow will fall after 5 p.m. Temperatures at 7,000 feet remained below freezing most of last night. This may have turned wet surface snow into a widespread crust and bedsurface. Moderate to strong southerly winds will create wind slabs atop this bedsurface on leeward aspects

Human triggered avalanches will be possible. As you transition to above treeline elevations where new snow is falling, look for shooting cracks or blocking snow in wind drifted areas of no consequence. This is a sign that wind slabs are forming. Avoid steep leeward slopes.

Forecast Discussion

Plenty of rain and snow will fall by early next week. Expect avalanche danger to be heightened over the next few days. Evaluate snow and terrain carefully as you travel in the backcountry. Keep the 5 red flags of avalanche danger in mind:

  • Recent avalanches
  • Cracking, blocking, or whumphing
  • Signficant snowfall in 24 hours
  • Strong winds
  • Temperature rise

Recent Observations

Observations at 7,000 ft on Mount Shasta in the last 24 hours:

  • TEMP: Near treeline (high/low): 30/34 deg F
  • PRECIP: 0.07" SWE
  • WIND: West/southwest, averaging 7 mi/hr, gusting to 18 mi/hr

Near and below treeline snow surfaces have been very wet from rain on snow and above freezing temperatures, though no notable signs of loose wet or cornice breaks have been observed. Boot penetration is up to two feet in places.

Weather and Current Conditions

Weather Summary

The lull in precipitation ends this afternoon as a series of fronts begin to move through the area. Over the next 24 hours expect 0.76 inches of precipitable water, the bulk of which will come after 5 p.m. Southerly winds will be moderate to strong near and above treeline. Elevations above 6,000 ft could see 4-11 inches of snow.

Similar conditions will continue through late afternoon tomorrow, with 0.48 inches of precipitable water, 3-7 inches of snow above 6,000 ft, and moderate to strong southerly winds.

The rain weary will get no rest as an atmospheric river event begins Saturday afternoon.

24 Hour Weather Station Data @ 5:00 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) 45 39 52 45.5 1 N
Sand Flat (6750 ft) 33 32 37 34 132 72 0 1.5
Ski Bowl (7600 ft) 29 29 34 30.5 175.7 0.4 0.07 2.2
Gray Butte (8000 ft) 27 27 33 30 7 18 WSW
Castle Lake (5870 ft) 33.5 32 43 36 133.7 3.4 3.5
Mount Eddy (6509 ft) 32 31.5 42.5 35 1 9 S 133.5 102.1 0.5
Ash Creek Bowl (7250 ft)
Ash Creek Ridge (7895 ft)

Two Day Mountain Weather Forecast

Produced in partnership with the Medford NWS

For 7000 ft to 9000 ft
  Thursday Thursday Night Friday (5 a.m to 5 p.m.)
Weather Rain and snow showers. Blustery. Chance of precipitation is 90%. Rain and snow showers, becoming all snow after 11 p.m. Blustery. Chance of precipitation is 100%. Snow. The snow could be heavy at times. Windy. Chance of precipitation is 100%.
Temperature (°F) 33 31 36
Wind (mi/hr) South 10-15 South 15-20 South 20-25
Precipitation SWE / Snowfall (in) / 0.5-2 / 4-7 / 3-5
For 9000 ft to 11000 ft
  Thursday Thursday Night Friday (5 a.m to 5 p.m.)
Weather Snow showers. Windy, gusty, and low wind chills. Chance of precipitation is 90%. Snow before 11 p.m., then snow showers after 11 p.m. The snow could be heavy at times. Windy, gusty, and low wind chills. Chance of precipitation is 100%. Snow. The snow could be heavy at times. Windy, gusty, and low wind chills. Chance of precipitation is 100%.
Temperature (°F) 24 20 21
Wind (mi/hr) South 30-35 Southwest 1-2 Southwest 35-55
Precipitation SWE / Snowfall (in) / 1-2 / 6-9 / 4-7

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2018 (the wet season) 35.52 35.81 99
Month to Date (since Jun 1, 2019) 0.30 0.35 86
Year to Date (since Jan 1, 2019) 27.11 20.60 132

Disclaimer

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