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Avalanche Advisory for 2013-12-20 07:22:16

  • EXPIRED ON December 21, 2013 @ 7:22 am
    Published on December 20, 2013 @ 7:22 am
  • Issued by -

Season's Greetings and Happy Holidays!

The Mt Shasta Avalanche Center, while eagerly waiting for snow, is busy planning for a great season.

Winter officially begins tomorrow and snow will start falling then, right?

The rockfall danger is currently rated at moderate to considerable. wink

Stay tuned for always the latest.

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

No current avalanche forecast is available

No current avalanche forecast is available

Avalanche Problem 1: Normal Caution

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The avalanche danger on Mt Shasta's glaciers is low. Skiing on the glaciers at this time is rough, icy and new snow from the past couple weeks is scarce. Any skiing on the north or east side glaciers would be not for the faint of heart! Be cautious of open bergshrunds, crevasses, ice patches, and rock/ice fall. Self arrest may be difficult with current conditions.


 

Recent Observations

Patchy snow up to 7 inches deep can be found above 6,500 feet in shaded areas and on northerly slopes. Areas that host the most snow (cold, north facing aspects) consist of sugary, faceted snow with a sun crust on top. When winter decideds to start, we will be watching these lower faceted/crust layers as new snow piles up.

The Everitt Memorial Highway, past the locked gate at Bunny Flat, is covered in snow and would allow cross-country skiing for 3 miles up into the Old Ski Bowl parking lot. The Sand Flat winter trails are also covered in a small amount of snow and folks have been xc-skiing out there. The west side of the forecast area has less snow.

Waiting....


A current look at our situation on the South side of Mt. Shasta, photo taken 12-18-13.
Please hold your comments like, "Ohhh...", "Ouch", or "Oooo"... we know. It's bad. angry

The North Side of Mt. Shasta with the Hotlam Glacier in center, taken 12-18-13.


The East side of Mt. Shasta, taken 12-18-13

Terrain:  Remember most of the terrain that we like to play on is greater than 30 degrees.  Avalanches are possible on anything steeper than 30 degrees.  Avoid cornices, rock bands, terrain traps and runout zones of avalanche paths.

Weather:  Most of our areas avalanche danger will occur 24-48 hours after a storm. We still can see persistent weak layers from time to time and we always will be sure to let you know about that!  Heed the basic signs: Wind (significant snow transport and depositions), Temperature (rain/snow/rain/snow, which in turn weakens the snowpack), and Precipitation (Snow or rain add weight and stress to the current snowpack).

SnowpackIf snow accumulates, give the snowpack a chance to adjust to the new snow load before you play on or near steep slopes (greater than 30 degrees).  Most direct action avalanches occur within 24-48 hours of recent snowfall.  Watch for obvious signs of snowpack instability such as recent natural avalanche activity, collapsing of the snowpack (often associated with a “whumphing” sound), and shooting cracks. If you see these signs of instability, limit your recreation to lower angle slopes.

Human Factor: Don’t forget to carry and know how to use avalanche rescue gear. You should NOT be skiing or climbing potential avalanche slopes without having beacons, shovels, and probes.  Only one person in a group should be exposed to potential avalanche danger at a time.  Remember, climbing, skiing, and riding down the edge of slopes is safer than being in the center.  Just because another person is on a slope doesn’t mean that it is safe.  Be an individual!  Make your own decisions.  Heed the signs of instability: rapid warming, “whumphing” noises, shooting cracks, snowing an inch an hour or more, rain, roller balls, wind loading, recent avalanche activity.

 


 

    Weather and Current Conditions

    Weather Summary

    In Mt Shasta City this morning at 0500, we have clear skies with a current temperature of of 27F.

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

    Old Ski Bowl - 7,600 feet, we have no new snow, with a snow depth total of appoximately 7 inches in shaded and/or northerly facing areas. The current temperature is 48F with a low of 14F and a high of 48F.

    Gray Butte - 8,000 feet, the current temperature is 40F. Temps have ranged from a low of 13F to a high 40F. Winds have average 15mph from the east until 2000 and then switched to southwest and averaged 9mph. Gusts hit 49 mph from the southwest and east/northeast.

    Castle Lake and Mt Eddy (West side of I-5)... 

    Castle Lake - 5,600 feet, the current temperature is 25F with a low of 18F and a high of 25F. No new snow overnight with a current snowpack of about 5-6 inches in more shaded areas.

    Mt Eddy - 6,500 feet, the current temperature is 29F with a low of 16F and a high of 29F. Winds have been calm, averaging 3 mph with gusts to 21 mph, south/southwest.

    THIS SEASON:  Since September 1st, we have received 2.82 inches of water, normal is 12-71 inches, putting us at 22% of normal. For the month of December, Mt Shasta has received .24 inches of water with normal being 4.68 inches, which is 5% of normal. For the year, Mt Shasta has received 10.00 inches of water, normal is 40.04 inches, putting us at 24% of normal for 2013.

    "Drought" and "driest" are words being spoken by weather professionals these days. It appears that we will decidedly break the record for driest calendar year on record. The 1981 to 2010 normal for water in Mt. Shasta is 43.21". Last December, alone, was wetter than this calendar year has been (10.43")!

    WEATHER SYNOPSIS:

    High pressure offshore is parked and north flow prevails. We may see a few snow flakes in the sky today, but don't expect anything to pile up. It will be VERY windy above treeline on the mountain. Shastafarians and the North State continue to wait for measureable snow to kick off the snow sports season. Even more disconcerting is this: " IN THE EXTENDED THERE STILL APPEARS TO BE NO INDICATION OF A BREAK DOWN IN NORTH TO NORTHWEST FLOW OVER THE REGION, AS HIGH PRESSURE REMAINS ANCHORED OFFSHORE. AT THIS POINT IT APPEARS WE WILL REMAIN IN THE SAME WEATHER PATTERN THROUGH THE END OF THE MONTH- THAT IS, FOG AND LOW CLOUDS WITH AN INVERSION MOST OF THE TIME WITH COLD TEMPERATURES AND THE POTENTIAL OF LIGHT PRECIPITATION LESS OFTEN." -NWS Medford, Brett Lutz

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    CURRENT CONDITIONS at Bunny Flat (6950 ft)
    0600 temperature: 35
    Max. temperature in the last 24 hours: 48
    Average wind direction during the last 24 hours: Southwest to Northeast
    Average wind speed during the last 24 hours: 15mph mi/hr
    Maximum wind gust in the last 24 hours: 49mph mi/hr
    New snowfall in the last 24 hours: 0 inches
    Total snow depth: 0-7 inches

    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 Partly sunny, very slight chance of snow flurries. Breezy Partly cloudy, small chance of snow flurries, clearing Clearing, Sunny
    Temperature (°F) 39 31 37
    Wind (mi/hr) North/Northwest 15-25mph Northwest 15-25mph North/northwest 15-25mph
    Precipitation SWE / Snowfall (in) / Trace / Trace / 0
    For 9000 ft to 11000 ft
      Friday Friday Night Saturday
    Weather Partly sunny, very windy Partly cloudy, slight chance of snow flurries, clearing Clearing, Sunny
    Temperature (°F) 36 30 34
    Wind (mi/hr) North 50-60mph, with gusts to 80mph North/Northwest Trace North/Northwest 60-70mph, decreasing
    Precipitation SWE / Snowfall (in) / Trace / trace / 0

    Disclaimer

    This advisory does not apply to Ski Areas or Highways and is for the Mt. Shasta, Castle Lake and Mt. Eddy back country. Use this information for guidance only. You may find different conditions in the back country and should travel accordingly. This advisory expires on midnight of the date it was posted unless otherwise noted.