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Avalanche Advisory for 2018-02-01 06:35:14

  • EXPIRED ON February 2, 2018 @ 6:35 am
    Published on February 1, 2018 @ 6:35 am
  • Issued by Nick Meyers - Shasta-Trinity National Forest

The avalanche danger is LOW for all elevations and aspects throughout the forecast area. Practice safe travel protocols and watch for unstable snow on isolated terrain features. Watch for falling rime ice above treeline.

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

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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
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    Very Large
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Natural and human triggered wind slabs are unlikely. Small wind slabs may be found in isoloated areas on SE-E-NE aspects above 9000 ft. Avoid wind loaded slopes steeper than 35 degrees. Check for the presence of wind slabs by looking for cornices, blowing snow, wind pillows, and hollow sounding snow.

Advisory Discussion

Alpine rock features on Mount Shasta are covered with rime ice. Warm weather will cause ice to dislodge and fall onto humans below. Be careful below Casaval Ridge, the Trinity Chutes, Green Butte/Sargents Ridges and Redbanks. Wear a helmet. Carry an ice axe and crampons.

Recent Observations

Temperatures have been above freezing at 8000 ft for the last 72 hours. Moderate to strong northwesterly winds have prevailed averaging 21 mi/hr. A wind slab (HS-N-D1.5-2) was observed yesterday on the SE aspect of Sun Bowl, however the actual occurrence of this slide is uncertain. It is suspected to be a few days old. Wind has been successful at transporting snow, though most of it is moving off the mountain or into low lying convexities, gullies, etc. Ridgetop wind loading has not been observed. It is a mixed bag out there, depending on your aspect and elevation. Below treeline, the top 4 to 6 inches of snow was moist to wet yesterday, mid-day. Near and above treeline, moist to dry snow surfaces exist. The combination snow platter will serve up sun crusts, wind crusts, sastrugi, wind eroded features, scoured old snow surfaces as well as smooth areas. Melt-freeze, corn snow is possible by the weekend. 

 

 

 

Weather and Current Conditions

Weather Summary

A warm front passes through today. Partly cloudy skies is all we shall receive, perhaps fog in valley bottoms. The forecast for the remainder of the week remains quiet with the worn out question: When will more snow arrive? One month temperature and precipitation models displayed below, pulled from the NOAA Climate Prediction Center. At this point, we're looking at above normal temperatures and below normal precipitation. Can we cry snowflakes?



                                                                                                     crying

 

 

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) 40 33 55 43 2 N
Sand Flat (6750 ft) 39 36 45 41 23 0 0 0
Ski Bowl (7600 ft) 42 34 47.5 40.5 43 0 0 0
Gray Butte (8000 ft) 38 34.5 43.5 38.5 13 55 NW
Castle Lake (5870 ft) 39.5 35.5 47.5 41 10 0 2
Mount Eddy (6509 ft) 40 34 44 39.5 1 10 ESE 25 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
  Thursday Thursday Night Friday
Weather Partly cloudy Partly cloudy Sunny
Temperature (°F) 47 36 50
Wind Direction Northwest Northwest Northwest
Wind Speed (mi/hr) 5-10 mi/hr 5-10 mi/hr 5-10 mi/hr
Expected Snowfall (in) 0 0 0
For 9000 ft to 11000 ft
  Thursday Thursday Night Friday
Weather Partly cloudy. Windy Partly cloudy. Windy Sunny. Breezy
Temperature (°F) 34 34 36
Wind Direction West Northwest Northwest
Wind Speed (mi/hr) 20-30 mi/hr 15-25 mi/hr 10-20 mi/hr
Expected Snowfall (in) 0 0 0

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2017 (the wet season) 10.11 22.27 45
Month to Date (since Nov 1, 2018) 4.28 7.06 61
Year to Date (since Jan 1, 2018) 4.28 7.06 61

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.