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Avalanche Advisory for 2014-03-15 06:07:39

  • EXPIRED ON March 16, 2014 @ 6:07 am
    Published on March 15, 2014 @ 6:07 am
  • Issued by Nick Meyers - Shasta-Trinity National Forest

Today, the avalanche danger is LOW for all elevations and aspects. Normal caution is advised.

LOW avalanche danger means that natural and human triggered avalanches are unlikely, but not impossible.

ALWAYS carry a beacon, shovel, probe and know how to use them...and wear a helmet!

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: Normal Caution

  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Overall, LOW avalanche danger exists for all elevations and aspects on Mt Shasta. Remember, LOW avalanche danger means natural and human triggered avalanches are unlikely, but not impossible. One could see small avalanches in isolated areas or extreme terrain.

Any instabilities today will be in the form of very small wind slabs above treeline, stubborn to unreactive to trigger and, wet loose avalanches on southerly aspects during the warmest hours of the day, likely in the form of roller balls and pinwheels.


Recent Observations

Concern for lingering wind slabs is falling and we are moving into a good melt/freeze cycle on southerly aspects. Mt Shasta is the only option for skiing in the area as Mt Eddy and Caslte Lake still have shallow snowpacks. Shasta's snowpack is typified by generally smooth snow with patches of wind erosional features dotting the landscape. Up higher on the mountain, expect a mix of wind features, icy patches and smooth snow. As we move into the climbing season, make sure to know how to use your ice axe and crampons and have self arrest skills. Further, wear a helmet, AND carry a beacon, shovel and probe.

A tour up to Sargents Spur Ridge in the Old Ski Bowl yesterday noted old wind slab and cornice debris off of leeward, E/SE facing slopes from earlier this week. Very small wind slabs were also noted in areas along the ridge, however said slabs were pasted well onto the old snow and were unreactive to trigger

Primary concerns will be rime icefall, rockfall, and failing to self-arrest on firm snow during early morning hours.


From Friday, 3-14-14:

Last weekend, Mt Shasta had a just over 1 inch of water fall on its flanks with snow levels fluctuating between 6,500 to 8,000 feet. This brought new snow to the mountain and was immediately followed by two days (Monday/Tuesday) of strong northwest winds and one day (Wednesday) of strong easterly winds. The new snow and wind created good conditions for wind slab avalanche potential on many aspects. On Monday (3-10-14), the MSAC got the report of a skier triggered (ascending) wind slab avalanche in the Anaconda drainage of Mt Shasta, approx. 9,200 feet. The avalanche was approx. 400' wide and ran 250' vertical feet. (HS-ASu-R2-D2-I) 3 people caught, partially buried, no injuries. (See photos below)

Another group of backcounytry skiers report seeing evidence of wind slab avalanches (debris) in the Hidden Valley area later in the week. It is likely that the mountain saw somewhat widespread avalanche activity early in the week during the wind event. Most of the slides were small to medium in size and the debris was subsequently eroded away by the wind after slides occured.

After the wind subsided, it turns out that most of our newer snow simply blew off the mountain. The mountain is currently hosting firm, wind blown conditions with pockets of wild looking wind erosional features. The best skiing has ended up being the old snow that is beginning to turn to "corn snow" in the afternoon hours. This weekend, some southerly slopes could host good spring like skiing. For climbers, conditions are getting good on all routes. However that being said, this is the time of year when the snow is smooth and firm, especially in the AM hours. A slip and fall on smooth, firm and sometimes icy snow can result in a slide for life. Self arrest skills with an ice axe and proper crampon use are essential for a safe climb. Further, a beacon/shovel/probe are absolutely recommended for any climbers attempting Shasta currently. Lastly, while the rockfall danger is low currently, rime ice can plaster exposed rocks on Shasta this time of year. As the days warm, the rime ice will flake off and fall onto climbers below, especially on the Avalanche Gulch route. Ice is like a rock and a HELMET should always be worn.

Photos below: Skier triggered wind slab avalanche on Mt Shasta, 3-10-14

Wind erosional feature in the Old Ski Bowl, 3-12-14

Aerial photo of the South side of Mt Shasta, taken by local pilot Troy Bainbridge just a few days ago.


While Northgate, Brewer Ck and Clear Ck trailheads are officially closed, the bathrooms are still open with packout bags inside, and one can still access the Mt Shasta Wilderness. However, your summit pass and wilderness permits must be purchased at McCloud or Mt Shasta Ranger Stations. NO DOGS are allowed in the Mt Shasta Wilderness OR Sierra Club Property. Thanks!


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 32 F.

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

    Old Ski Bowl - 7,600 feet. The Old Ski Bowl weather station has received no new snow in the last 24 hours. The current temperature is 33F with a low of 33F and a high of 44F. Total snow depth is 55 inches with 1 inch settlement.

    Gray Butte - 8,000 feet - The current temperature is 36F. Temps have ranged from a low of 33F to a high 42F.  Winds have been easterly and averaging 5-10 mph. Gusts hit 35 mph from the NNE yesterday at 0900.

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

    Castle Lake - 5,600 feet, the current temperature is 37F with a low of 36F and a high of 49F. Castle Lake has received no new snow and has a current snowpack of 1-3 inches with little settlement.

    Mt Eddy - 6,500 feet, the current temperature is 30F with a low of 30F and a high of 43F. Mt Eddy has received no new snow and hosts a current snow depth of 19 inches. Winds have averaged 3 mph from the ESE up until 1600 and then switched to WSW. Gusts reached 14 mph from the ESE at 1400.

    THIS SEASON: Since September 1st , we have received 11.28 inches of water, normal is 33.47 inches, putting us at 33% of normal. For the year of 2014, Mt Shasta has received 8.46 inches of water with normal being 17.59 inches which puts us at 48% of normal. And lastly, for March we sit at 73% of normal, receiving 2.42 inches of water, normal is 3.30 inches.


    Today will be a beautiful day highlighted by light winds and glorious spring sun! Nothing much to note in the way of inclement weather on this fine Saturday. West/Northwest winds will increase through the weekend and a slight chance of precip exists for late Sunday.

    CURRENT CONDITIONS at Bunny Flat (6950 ft)
    0600 temperature: 34
    Max. temperature in the last 24 hours: 44
    Average wind direction during the last 24 hours: Easterly
    Average wind speed during the last 24 hours: 5-10 mi/hr
    Maximum wind gust in the last 24 hours: 35 mi/hr
    New snowfall in the last 24 hours: 0 inches
    Total snow depth: 55" inches

    Two Day Mountain Weather Forecast

    Produced in partnership with the Medford NWS

    For 7000 ft to 9000 ft
    (4 a.m. to 10 p.m.)
    Saturday Night
    (10 p.m. to 4 a.m.)
    (4 a.m. to 10 p.m.)
    Weather Sunny Clear Sunny
    Temperature (°F) 55 31 54
    Wind (mi/hr) South/Southwest Light Southwest 5-10mph South/Southwest 5-10 mph
    Precipitation SWE / Snowfall (in) / 0 / 0 / 0
    For 9000 ft to 11000 ft
      Saturday Saturday Night Sunday
    Weather Sunny Clear Sunny
    Temperature (°F) 42 26 42
    Wind (mi/hr) West 5-15 mph West/Southwest 0 West/Southwest 20-30 mph
    Precipitation SWE / Snowfall (in) / 0 / 0 / 0


    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.