You are here

Avalanche Advisory for 2018-02-18 07:00

  • EXPIRED ON February 19, 2018 @ 7:00 am
    Published on February 18, 2018 @ 7:00 am
  • Issued by Andrew Kiefer - Mt Shasta Avalanche Center

Avalanche danger is LOW and NORMAL CAUTION is advised. Firm and icy snow surfaces are widespread and shallow snowpack hazards exist. An incoming storm today will bring dangerously cold temperatures, light snowfall and gale-force winds out of the northwest. Whiteout conditions are expected on Mount Shasta by this afternoon.

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.

Forecast Hotline: (530) 926-9613

Avalanche Problem 1: Normal Caution

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

NORMAL CAUTION means:

  • Watch for isolated slabs.
  • Ski and ride one at a time in avalanche terrain.
  • Don't regroup in run out zones.
  • Basic avalanche rescue skills are essential in avalanche terrain.

Isolated slabs are related to wind and terrain. Look for areas of drifting snow. This will occur on the lee side of ridges, in terrain depressions, on convex terrain features, and in the lee of isolated bands of trees.

Forecast Discussion

Today’s storm will create challenging and cold conditions in the backcountry. Northwest winds paired with 2-4 inches of snow over the next 24 hours may create isolated and shallow wind slabs in leeward terrain near and above treeline. Watch for wind slab development as snow begins to accumulate. This system will favor areas just north of Mount Shasta where significantly more snow is expected. Snow forecasts of 2-4 inches for our advisory area are generous, and 1-2 inches may be more realistic. Expect gale-force, northwest winds above 8,000 ft and limited visibility. Temperatures are dropping quickly and lows tonight will be below 0° F above treeline. Avalanche danger will remain LOW today and NORMAL CAUTION is advised.

Recent Observations

Submit Snowpack Observations
Submit Avalanche Observations

No new snow has fallen as of 7 am this morning and skies are clear. Over the past 24 hours, temperatures have ranged from 18-51° F throughout the advisory area with a high of 59° in Mount Shasta City. Winds have blown 20-30 mph with gusts to 49 mph out of the W/NW at 8,000 ft on Grey Butte.

The upper mountain remained in the clouds yesterday with periods of sunshine below. Snow surfaces were soft and moist up to 9,500 ft, while above they were firm and icy. The snowpack above 7,000 ft is 1-4 ft deep and comprised mostly of melt-freeze crusts and ice layers. Coverage is sparse below treeline. Snow on the road to the Old Ski Bowl is thin.

The upper Sand Flat road and cross-country ski trails are rough and firm. The lower road and trails have very little snow.

The Castle Lake and Mount Edddy areas have 8 to 12 inches of snow but coverage is inconsistent. Winter recreation is limited.

No avalanches or evidence of unstable snow have been observed this month.

Weather and Current Conditions

Weather Summary

A strong cold front will impact northern California bringing snow showers, very cold temperatures and northwest winds. The National Weather Service has issued a WINTER WEATHER ADVISORY IN EFFECT UNITL 4AM PST MONDAY. Temperatures will drop to the teens and single digits late this afternoon with wind chill values well below zero. Periods of light snow showers are expected over the next 24 hours with snow down to town level. With .15 inches of water forecast, 2-4 inches of snow will be possible in the mountains while 1-2 inches should fall in town. Skies will clear mid-day tomorrow and temperatures will remain cold. Wednesday and Thursday will bring another chance for light snow showers.

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) 37 29 59 44.5 1 N
Sand Flat (6750 ft) 27 27 45 36 18 0 0 0
Ski Bowl (7600 ft) 20 20 45.5 32.5 38.5 0 0 0
Gray Butte (8000 ft) 19 19 41 31.5 17 49 WNW
Castle Lake (5870 ft) 27 27 51.5 38 8 0 0
Mount Eddy (6509 ft) 24 24 46.5 36 2 17 SSE 22 0 0
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
(4 a.m. to 10 p.m.) 		Sunday Night
(10 p.m. to 4 a.m.) 		Monday
(4 a.m. to 10 p.m.)
Weather Snow shower and breezy. Chance of precipitation is 90%. Snow showers likely. Chance of precipitation is 70%. A chance of snow showers mainly before 4am. Chance of precipitation is 30%. Wind chill values as low as -7.
Temperature (°F) 27 13 18
Wind (mi/hr) W 15-20 mi/hr W/NW 10-15 mi/hr N/NW 10-15 mi/hr
Precipitation SWE / Snowfall (in) / 2-4 / 1-2 / < .5
For 9000 ft to 11000 ft
  Sunday Sunday Night Monday
Weather Snow showers and windy. Chance of precipitation 90%. Wind chill values as low as -35. Snow showers likely and windy. Chance of precipitation is 70%. Wind chill values as low as -37. A 30 percent chance of snow showers mainly before 10am. Wind chill values as low as -38. Windy.
Temperature (°F) 3 -5 -3
Wind (mi/hr) W 40-50 mi/hr NW 3-5 N 30-40 mi/hr
Precipitation SWE / Snowfall (in) / 3-5 / 1-2 / < .5

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2023 (the wet season) 10.19 26.21 39
Month to Date (since Apr 1, 2024) 0.08 3.94 2
Year to Date (since Jan 1, 2024) 4.36 11.00 40

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.