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Avalanche Forecast for 2019-03-11 06:00

  • EXPIRED ON March 12, 2019 @ 6:00 am
    Published on March 11, 2019 @ 6:00 am
  • Issued by Ryan Sorenson - Mount Shasta Avalanche Center

Triggering an avalanche is unlikely however not impossible today. Watch out for lingering wind slab avalanches in isolated steep terrain. Remaining wind slabs are presumably small and are becoming more difficult to trigger. Use normal caution and pay attention to windblown snow and areas of drifting. 

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

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

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

Calm to light winds and increasing temperatures yesterday has decreased the likelihood of triggering a wind slab avalanche today. Wind slabs could be found on isolated terrain near and above treeline. Look for these primarily on W-NW-N-NE-E aspects. However, a wind slab could form in any steep leeward terrain. These will likely remain small but could pose a greater risk in complex terrain or over terrain traps. Triggering a large wind slab is unlikely, however not impossible. 

Use normal caution and pay attention to where leeward areas reside if venturing out into steep terrain today. Look for signs of wind slabs and cornices as you travel. Stay away from areas where shooting cracks, blocking, and whumphing are observed. Other signs of wind slabs include previously drifted snow and chalky, hollow sounding snow.

If wind slabs are encountered keep travel to a lower angle, windward slopes to return to safety. Identify features of concern. Travel one at a time in steep leeward terrain. Choose appropriate safety zones. Basic avalanche rescue skills are always necessary when you travel in avalanche terrain.

Recent Observations

In the last 24 hours:

The temperatures have varied with a maximum temperature of 25 degrees F and a minimum of 17.5 degrees F at 8,000 feet on Mount Shasta. Light to moderate wind speeds with an average of 12 mi/hr out of the northeast was recorded last night.

The temperature in the Eddies ranged from 23 to 38 at 5,800 feet at Castle Lake and 14 to 29 at 6,500 feet on Mount Eddy.  Calm to light winds was observed across the Eddies. 

Snowpack conditions:

  • Precip: +/- 6 inches of new snow recorded at Old Ski Bowl in the last 48 hours.
  • Settlement of 2-3 inches in the last 24 hours.
  • New snow sit on top of a supportable crust above a previously upside down storm snow layering observed: moist, heavy snow on top, dryer snow below.
  • Stability tests have shown some planar results on density changes in old and new snow layers across the forecast area.
  • Snowpack has settled and is showing a trend towards stability.
  • Large cornice features exist on ridgelines across the forecast area.

Weather and Current Conditions

Weather Summary

Pack your sunblock, the fireball will be back in a clear blue sky today. Light to moderate northeast wind in the early morning will give way to calm and clear conditions this afternoon. Expect warming temperatures with a high in the lower to mid-40s on Mount Shasta. Don't get caught in your shorts this evening, winter will return to the forecast area tonight signaled by building clouds with calm to light east wind. More cold snow showers with snow level as low as 3,700 feet are expected tomorrow.  Snow accumulation of an inch or two will fall by Wednesday. 

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) 29 24 45 33 0 N
Sand Flat (6750 ft) 13 13 33 24 150 1 0 3
Ski Bowl (7600 ft) 22.5 18 26.5 21 187 1 0.27 2
Gray Butte (8000 ft) 23 17.5 25 21 12 31 ENE
Castle Lake (5870 ft) 23.5 22.5 38.5 28 147 1 3
Mount Eddy (6509 ft) 14 14 29.5 21.5 2 7 WSW 141 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
  Monday
(5 a.m to 11 p.m.)
Monday Night
(11 p.m. to 5 a.m.)
Tuesday
(5 a.m to 11 p.m.)
Weather Sunny Becoming mostly cloudy Snow in the morning then a chance of snow showers. Snow levels at 3k to 4k Feet.
Temperature (°F) 40 20 35
Wind (mi/hr) Northeast 0-5 Northwest 0-5 Northwest 5-10
Precipitation SWE / Snowfall (in) / 0 / 0 / 0-2
For 9000 ft to 11000 ft
  Monday Monday Night Tuesday
Weather Sunny Becoming mostly cloudy Snow in the morning then a chance of snow showers. Snow levels at 3k to 4k Feet.
Temperature (°F) 25 20 20
Wind (mi/hr) East 5-15 Northwest 0 Northwest 25-30
Precipitation SWE / Snowfall (in) / 0 / 0 / 0-2

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2019 (the wet season) 31.70 31.92 99
Month to Date (since Apr 1, 2020) 2.17 2.42 90
Year to Date (since Jan 1, 2020) 23.29 16.71 139

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.