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Avalanche Advisory for 2017-03-24 06:37:53

  • EXPIRED ON March 25, 2017 @ 6:37 am
    Published on March 24, 2017 @ 6:37 am
  • Issued by Nick Meyers - Shasta-Trinity National Forest
  • March 24, 2017 @ 6:37 am

    Advisory Hotline: (530) 926-9613

  • Wind slab avalanches will be likely for human trigger today above treeline due to new snow and windy conditions. Expect CONSIDERABLE danger above treeline in exposed areas, along ridgelines and near the edges of open bowls. Some isolated, exposed areas near treeline could experience CONSIDERABLE danger as well, however near treeline MODERATE danger will prevail overall. Below treeline, avalanche danger is LOW. 

  • Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

Avalanche Problem 1: Wind Slab

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The wind slab avalanche problem near and primarily above treeline will be today's concern. New and existing wind slabs are fair game for human trigger. Several inches of new snow and windy southwesterlies will load leeward N-NE-E aspects. Existing wind loaded S-SE aspects may host thicker wind slabs and be suspect as well. Touchy conditions can be expected today, especially this morning, and a human triggered wind slab is likely along exposed ridgelines and bowls where evidence of wind loading is observed. Play it safe!

 

 

 

 

Recent Observations

We've had .36 inches of precipitation (SWE) fall overnight, starting at 2000 hours. This has translated to about 3-5 inches of new snow. Temperatures are about 5 degrees warmer this morning. Winds blew 5-10 mph on average with gusts to 15-20 mph out of the west/northwest up until the onset of the storm, switching to south/southwest at the same time, about 1900 to 2000 hours. 

East/Southeast aspects above treeline have experienced both natural and rider triggered wind slabs over the past several days including one snowmobile triggered wind slab yesterday. These slides were small to medium sized avalanches. Some loose snow surface sluffing was easily initiated below ski and snowmobile tracks as well. 

 

Weather and Current Conditions

Weather Summary

A Winter Weather Advisory remains in place, issued by the NWS Medford, until 2 PM PDT this afternoon... expect snow this morning, heavy at times. This afternoon, precipitation will taper off and showery conditions will bring us into the evening. Up to an additional .5 inches of water is forecasted, but I don't think we will see that much. Snow levels will hover around 3,900 feet today, 4,600 feet tonight and tomorrow. Today will be windy out of the south, tapering off later this afternoon. Overall, while we may see short periods of clearing and perhaps a peeking sun tomorrow, the weekend appears to be mostly cloudy with addtional precipitation on Sunday. 

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In Mt Shasta City at 0500, we have a current temperature of 33 F.

On Mt Shasta (South Side) in the last 24 hours...

Sand Flat - 6,750 ft, the current temperture is 26 degrees F.  Temperatures have ranged from 17 F to 37 F.  Snow on the ground totals 110 inches with 2-4 inches of new snow and little settlement.

Old Ski Bowl - 7,600ft. the current temperature is 23 degrees F.  Temperatures have ranged from 15 F to 35 F.  Snow on the ground totals 190 inches with 4-6 inches of new snow and little settlement. 

Gray Butte - 8,000 feet, the current temperature is 22 degrees F. Temperatures have ranged from 19 F to 32 F.  Winds have averaged 5-10 mph with gusts to 15-20 mph, blowing from the WNW up until 1900 hours, then switching to S/SW.

Mt Eddy Range (West side of Interstate-5)... 

Castle Lake - 5,800 feet, the current temperature is 26 degrees F. Temperatures have ranged from 24 F to 41 F. Snow on the ground totals 97 inches with 2-4 inches of new snow and little settlement.

Mt Eddy - 6,500 feet, the current temperature is 24 degrees F. Temperatures have ranged from 16 F to 35 F. Snow on the ground measures 92 inches with 1-2 inches of new snow and little settlement. Winds have been southerly averaging 2-3 mph with gusts up to 12 mph.

THIS SEASON PRECIPITATION for MT SHASTA CITY: Since October 1st (the wet season), we have received 47.63 inches of water, normal is 34.36 inches, putting us at 138% of normal.  For the month of March, we have received 4.32 inches of water, normal is 4.86 inches, which is 88% of normal. And finally for the year of 2017, we received 26.47 inches of water, normal is 19.15 inches, putting us at 138% of normal.

Always check the weather before you attempt to climb Mt Shasta. Further, monitor the weather as you climb. Becoming caught on the mountain in any type of weather can compromise life and limb. Be prepared.

24 Hour Weather Station Data Fetched @

Weather Station Temp (°F) Wind (mph) Snow (in) Comments
Cur Min Max Avg Cur Min Max Avg Max Gust Dir Depth New Water Equivalent Settlement
Mt. Shasta City (3540')
Sand Flat (6750')
Ski Bowl (7600')
Grey Butte (8000')
Castle Lake (5870')
Mount Eddy (6509')
Ash Creek Bowl (7250')
Ash Creek Ridge (7895')

Two Day Mountain Weather Forecast

For 7000 ft. to 9000 ft.
  Friday Friday Night Saturday
Weather Snow before 11am, then snow showers after 11am. The snow could be heavy at times. Breezy. Chance of precipitation is 100%. Snow showers, mainly before 11pm. Chance of precipitation is 80%. A 20 percent chance of snow showers. Partly sunny.
Temperatures 36 deg. F. 26 deg. F. 39 deg. F.
Wind direction South South Southwest
Wind speed 15-20 mph 5-10 mph 5 mph
Expected snowfall 4-6 in. 1-3 in. 0 in.
For 9000 ft. to 11000 ft.
  Friday Friday Night Saturday
Weather Snow before 11am, then snow showers after 11am. The snow could be heavy at times. Windy. Wind chill values as low as -7. Chance of precipitation is 100%. Snow showers, mainly before 11pm. Low around 13. Windy. Wind chill values as low as -10. Chance of precipitation is 80%. A 20 percent chance of snow showers. Partly sunny. Windy. Wind chill values as low as -9.
Temperatures 20 deg. F. 13 deg. F. 17 deg. F.
Wind direction Southwest Southwest West
Wind speed 40-45 mph 20-25 mph 15-20 mph
Expected snowfall 4-6 in. 1-3 in. 0 in.

Disclaimer

This advisory 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 advisory expires on midnight of the date it was posted unless otherwise noted.