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Avalanche Forecast for 2019-12-13 06:02

  • EXPIRED ON December 14, 2019 @ 6:02 am
    Published on December 13, 2019 @ 6:02 am
  • Issued by Nick Meyers - Shasta-Trinity National Forest

LOW danger below and near treeline and MODERATE danger above treeline continues. Remain attentive for wind drifted snow at higher elevations on Mount Shasta. Gale force, westerly wind and a few inches of fresh snow is forecast for today.

 

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.

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

Forecast Hotline: (530) 926-9613

Avalanche Problem 1: Wind Slab

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  • Size ?
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Above treeline on Mount Shasta, fresh snow and strong westerly wind may form new, small wind slabs and/or increase size and distribution of existing wind slabs today. Easterly aspects is where you're most likely to find said wind slabs. The warm, moist nature of our recent storms has kept snow transport to a minimum at lower elevations and thus, wind slabs have been small and difficult to trigger. Colder, higher elevations may be different. Cornices, wind pillows and ridgetop scouring are good clues to determine where wind slabs could be near.

Forecast Discussion

Buried in an avalanche? Seconds matter. Shoveling is the most time consuming phase of an avalanche rescue. Learn the basics of strategic shoveling.

 

Recent Observations

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  • ​​​​​​In the last 24 hours at treeline on Mount Shasta, temperatures have ranged from 28 to 31°F with average wind speeds of 18 mi/hr, gusts to 37 mi/hr out of the west/northwest.
  • One to three inches of condensed, moist new snow.  Total height of snow 43 inches on a NW facing slope near treeline. A variety of crusts exist, some supportable on skis, not boots. Boot penetration 4 - 6 inches. Heavy mist formed a thin zipper crust on top of new snow above treeline. 
  • Precipitation: nil
  • Sky: cloudy/fog/poor visibility
  • Westerly wind blowing 15-20 mi/hr with gusts to 30 mi/hr
  • No recent avalanche activity or obvious signs of instability

Weather and Current Conditions

Weather Summary

Thus far, our spurts of rain and snow this week have been under-whelming. Out of all the rapid fire storms we've seen, today might be the most influential of the weather firing our way. This morning, satellite and radar models show precipitation arriving onshore and spreading inland, albeit slightly to the north of us. The westerly moving system will dump most of its precipitation along the coastal mountains. We should get seconds out of it. Snow levels will fall within the 5,500 to 6,000 foot range. Forecast models indicate 5 to 9 inches of snow at Bunny Flat today but I'd be surprised if we observe that much. However...when it comes to fresh snow, I love being fooled! Gale force wind blowing out of the west will be encountered above treeline.



BELOW: 6-10 day temperature and precipitation forecasts. More like these can be found HERE.

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) 39 29 43 36 2 N
Sand Flat (6750 ft) 32 32 34 33 31 0 0 0
Ski Bowl (7600 ft) 28.5 28 31 29.5 39.5 0 0 1
Gray Butte (8000 ft) 28 27 30 28.5 18 37 WNW
Castle Lake (5870 ft) 0 0 0 0 0 0 0 down
Mount Eddy (6509 ft) 31.5 30.5 36 33 1 12 SSE 26 0 1
Ash Creek Bowl (7250 ft) down
Ash Creek Ridge (7895 ft) down

Two Day Mountain Weather Forecast

Produced in partnership with the Medford NWS

For 7000 ft to 9000 ft
  Friday
(4 a.m. to 10 p.m.) 		Friday Night
(10 p.m. to 4 a.m.) 		Saturday
(4 a.m. to 10 p.m.)
Weather Snow, temperatures falling to 28 by 9am. Breezy. Chance of precipitation 100%. Snow levels near 5,800 feet. Snow showers, mainly before 10pm. Chance of precipitation 90%. Snow level near 4,800 feet. Snow showers, partly cloudy, clearing. Chance of precipitation 60%. Snow levels near town.
Temperature (°F) 33 23 29
Wind (mi/hr) Southwest 10-15 West 5-10 Northwest 0-5
Precipitation SWE / Snowfall (in) 0.56 / 4-8 0.02 / 1-2 0.10 / 0-0.50
For 9000 ft to 11000 ft
  Friday Friday Night Saturday
Weather Snow, heavy at times. Windy. Wind chill as low as -7 F. Chance of precipitation 100%. Snow showers, mainly before 10pm. Chance of precipitation 90%. Windy. Wind chill values as low as -11 F. Snow showers, partly cloudy, clearing. Chance of precipitation 60%. Windy. Wind chill values as low as -17 F.
Temperature (°F) 22 11 11
Wind (mi/hr) West 40-50 West 30-40 Northwest 10-20
Precipitation SWE / Snowfall (in) 0.56 / 5-9 0.02 / 2-3 0.10 / 0-1

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2024 (the wet season) 7.77 10.18 76
Month to Date (since Dec 1, 2024) 5.09 2.82 180
Year to Date (since Jan 1, 2024) 45.51 38.18 119

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 24 hours after the posted time unless otherwise noted.