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Avalanche Advisory for 2018-03-08 06:00

  • EXPIRED ON March 9, 2018 @ 6:00 am
    Published on March 8, 2018 @ 6:00 am
  • Issued by Nick Meyers - Shasta-Trinity National Forest
  • March 8, 2018 @ 6:00 am

    Advisory Hotline: (530) 926-9613

  • Overnight, a couple inches of new snow accompanied by strong S/SW winds impacted higher terrain within the forecast area. New snow is available for transport and fresh wind slabs will form on leeward northerly and easterly terrain, near and above treeline. Periods of snow and continued high winds are expected today. Active wind loading will occur and human triggered wind slabs are possible. 




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

Avalanche Problem 1: Wind Slab

  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Look for blowing snow today, note where it's going and use caution on those slopes. Wind slabs can vary in size and depth. Wind slabs can be recognized by the appearance of the snow surface, changes in snow hardness, hollow drum-like sounds and/or shooting cracks. Identify specific terrain features of concern such as leeward aspects of ridgelines and steep, upper edges of bowls. Wind slabs are best managed by recognizing and avoiding areas where wind slabs have formed.


Advisory Discussion

If you plan on heading up above treeline today, be prepared for strong winds, wind chill and developing wind slabs on northerly and easterly aspects. Unsettled weather will continue through Friday.

Recent Observations

On Mount Shasta in the last 24 hours:

  • 2-4 inches of new snow fell overnight (.27 inches water from 2100 to 0300 hours)
  • Winds have organized out of the southwest, averaging 10-20 mi/hr with gusts 30-40 mi/hr
  • Temperatures have ranged from 24 to 35 deg F

Castle Lake:

  • 2+ feet of snow on the ground surrounding Castle Lake
  • Lake is frozen

Weather and Current Conditions

Weather Summary

A low pressure system moves inland today. Gusty winds are the main impact. Light rain and snow showers should persist through Friday. Several inches of snow can be expected above 6,000 feet by the weekend.  The heaviest precipitation with this system will be focused on the southern and western slopes of higher terrain. The extended forecast shows a period of mainly dry, mild weather with temperatures above normal.


24 Hour Weather Station Data @ 4:00 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) 40 35 54 42.5 3 ESE
Sand Flat (6750 ft) station down
Ski Bowl (7600 ft) 25 25 39.5 32 60 4 0.27 2.5
Gray Butte (8000 ft) 26.5 25 36 30.5 10 31 SSE
Castle Lake (5870 ft) 30 30 51.5 37.5 28 3 2.5
Mount Eddy (6509 ft) 25.5 25.5 43 34 2 18 SSW 46 3 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
  Thursday Thursday Night Friday
Weather Windy. Widespread rain and snow showers. Chance of precipitation 80%. Snow level 5,500 feet. Breezy, cloudy. Rain and snow showers. Chance of precipitation 80%. Snow level at 5,900 feet. Rain and snow showers. Chance of precipitation 80%. Snow level at 6,000 feet.
Temperature (°F) 34 34 36
Wind Direction S S S
Wind Speed (mi/hr) 10-20 mi/hr 10-15 mi/hr 5-10 mi/hr
Expected Snowfall (in) 1-2 3-5 2-3
For 9000 ft to 11000 ft
  Thursday Thursday Night Friday
Weather Snow showers and windy. Chance of precipitation 90%. Snow showers and windy. Chance of precipitation 100%. Show showers and windy. Chance of precipitation 100%.
Temperature (°F) 18 18 19
Wind Direction SW W W
Wind Speed (mi/hr) 40-50 mi/hr 30-40 mi/hr 10-20 mi/hr
Expected Snowfall (in) 2-4 3-5 2-4

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2017 (the wet season) 12.39 31.23 40
Month to Date (since Sep 1, 2018) 1.50 1.73 87
Year to Date (since Jan 1, 2018) 6.56 16.02 41


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.