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Avalanche Advisory for 2018-12-03 06:04

  • EXPIRED ON December 4, 2018 @ 6:04 am
    Published on December 3, 2018 @ 6:04 am
  • Issued by Nick Meyers - Shasta-Trinity National Forest

MODERATE avalanche danger exists near and above treeline today due to lingering wind slabs. Human triggered avalanches will remain possible. If any doubts exist about the stability of a slope, avoid it and move on to something lower angle. LOW danger remains below treeline. Rocks and other hazards still exists so be careful.

 

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

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

Continue to be mindful of the wind slab problem today. Wind slabs will mostly be encountered on SE-E-NE aspects but mountain winds are variable so look for them wherever there is evidence of wind loading. 

Evaluate snow and terrain carefully. Avoid wind slabs by traveling in windward areas where snow surfaces have been eroded. Avoid slopes greater than 35 degrees where wind loading has occurred. Evaluate conditions as you travel in safe terrain by looking for signs of the wind slab problem:

  • Smooth rounded wind pillows
  • Hollow sounding snow
  • Harder snow atop softer snow
  • Shooting cracks

Forecast Discussion

Temperatures will remain chilly today. If venturing out into the backcountry, bring appropriate clothing to stay warm!

Recent Observations

A series of winter storms beginning on Thanksgiving (November 22, 2018) has brought 50 inches of snow above 7000 ft. Current height of snow (HN) at the Old Ski Bowl weather station is 41 inches.

Yesterday brought clear skis, light winds and cool temps to the forecast area. Above 8,500 feet is wind affected. No new avalanches were observed. 

Early season obstacles are mostly covered however some hazards still exist. Tread lightly.

 

Weather and Current Conditions

Weather Summary

Dry and chilly conditions continue today accompanied by light winds at lower elevations and moderate winds at upper elevations. A small low pressure system may bring a chance of moisture back to the region Tuesday/Wednesday. Dry weather will follow for Thursday and Friday.

 

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) 19 19 39 27.5 1 N
Sand Flat (6750 ft) 10 10 24 16 31 1 0 2
Ski Bowl (7600 ft) 16.5 12 28 16 41.3 0.8 0 1.1
Gray Butte (8000 ft) 13.5 11.5 23.5 15.5 3 12 ESE
Castle Lake (5870 ft) 0 0 0 0 0 0 0 station down
Mount Eddy (6509 ft) 12.5 9.5 23 15.5 2 7 WSW 34 0.2 2.5
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
  Monday
(4 a.m. to 10 p.m.)
Monday Night
(10 p.m. to 4 a.m.)
Tuesday
(4 a.m. to 10 p.m.)
Weather Sunny A 30 percent chance of snow, mainly after 4am. Increasing clouds. A 30 percent chance of snow, mainly before 10am. Mostly cloudy.
Temperature (°F) 28 22 31
Wind (mi/hr) Calm, becoming SE in the afternoon 0-5 E/SE 5-10 SE 10-15
Precipitation SWE / Snowfall (in) / 0 / 0-.5 / 0-.5
For 9000 ft to 11000 ft
  Monday Monday Night Tuesday
Weather Sunny and windy A 30 percent chance of snow, mainly after 4am. Increasing clouds. A 30 percent chance of snow, mainly before 10am. Mostly cloudy.
Temperature (°F) 19 21 22
Wind (mi/hr) SW 10-15 W/SW 0 S 15-20
Precipitation SWE / Snowfall (in) / 0 / 0-.5 / 0-.5

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2023 (the wet season) 5.07 7.81 65
Month to Date (since May 1, 2024) 0.34 0.45 76
Year to Date (since Jan 1, 2024) 20.35 35.81 57

Disclaimer

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