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Avalanche Advisory for 2015-03-22 07:12:31

  • EXPIRED ON March 23, 2015 @ 7:12 am
    Published on March 22, 2015 @ 7:12 am
  • Issued by Jon Dove - Shasta-Trinity National Forest

The avalanche danger is currently LOW for all elevations and aspects, but may increase later today as new snow accumulates.  MODERATE avalanche danger could develop at near and above treeline by Monday morning with the forecasted new snow and winds. 

Normal caution advised.

Climbers should be heads up for ice fall and "slide for life" conditions.

Carry a beacon shovel and probe. Wear a helmet. Know how to use your ice axe and crampons.

 

 

 

 

 

 

 

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

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    Certain
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  • Size ?
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Low danger exists for today.

If you plan on heading up onto the mountain today or the begining of the week, expect cooling temperatures and winter weather. Snow with S-SW-W wind will cause the avalanche danger to rise over the next couple of days.

Don't let your guard down as winter weather has returned!

Recent Observations

Observations made yesterday at elevations near and slightly above treeline were consistent with the melt/freeze cycle meaning good corn snow and some softening in the early to mid afternoon making for great skiing conditions. The snow pack is well bonded and isothermal. No loose wet instabilities were observed.  That being said, a cold front has begun to push onshore bringing with it light preciptiation that has started to fall early today.  Temperatures will fall as the storm moves through with snow levels as low as 4000-5000 feet by tonight into early Monday. 

By 4 a.m. this morning  .05 inches of water was recorded at Old Ski Bowl weather station.  Precipitation amounts will increase through out the day with the heaviest periods of rain and snow falling late afternoon into this evening.  New snow totals of up to 10-12 inches are possible near and above tree line by Monday morning.  New snow will be accumulating on a firm old snow surface that could make for a good bed surface for new snow instabilities.  

Current avalanche danger is low, however, new snow and wind slabs will be our avalanche problems for Monday and Tuesday.  Higher winds of 35 to 40 mph out of the west-southwest with stronger gusts are forecast to accompany this storm.  This means that wind slab developement is possible on NW-N-NE-E-SE aspects.  Considering new snow totals, wind slabs that develop could be 2+ feet thick in some spots.  By Monday morning avalanche danger above tree line could rise to MODERATE depending on new snow totals and wind slab development.  Be cautious with route decision making, avoiding leeward apects, known avalanche paths, and run out zones.  

Photos:
Top - Casaval Ridge 3-18-15 [Bob Hutcheson]

Bottom - Wet/loose point releases, photo taken on 3-18 however slides occured earlier in the week, late Sunday/Monday. [Bob Hutcheson]

The snowpack is currently in a transitional phase: From 7,000 to about 8,500/9,000 feet, smooth, supportable melt/freeze snow can be found on warmer aspects, east and south. From +/- 8,500 feet and above, the snowpack is still transitioning. The danger is currently low, however keep your awareness up as we get new snow and increased wind today and tonight.  Below treeline, tree wells are showing and dirt patches exists, but will soon be covered by new snow amounts. 

Continue to always use safe travel methods: carry situational awareness on your skin up the mountain, choose safe routes and watch for what others are doing, ski one at a time, stop in safe zones!

For folks that plan on climbing Mt. Shasta:  Route conditions on Casaval Ridge, Sargents Ridge, and Avalanche Gulch are currently good.  That being said, the firm old snow surface will start to collect snow, and by tomorrow morning could be cover by up to a foot of new.  Should one slip and fall and are unable to self-arrest, a long tumble is a possibility.  Ice fall from rime ice that still partially covers the Red Banks and other rock outcroppings is happening, even in the early morning hours.  A helmet, crampons, and a mountain axe are necessary equipment and should be used. 

Castle Lake and Mt Eddy zones are still hosting a shallow snowpack. All areas below about 6,000 feet in the forecast area are hosting patchy snow with dirt showing around trees and in sunny spots.  For Castle Lake, skiing is out of the question at this point due to lack of snow.

Report your observations to the MSAC! A photo, a few words... send them in! (nimeyers@fs.fed.us or 530-926-9614)

Sand Flat Winter Trails: OPEN, however snow depths are meager and the Lower Sand Flat road is exposed dirt. We recommend heading up to Bunny Flat and touring up the road or anywhere higher in elevation!

Pilgrim Creek Snowmobile Park: CLOSED due to lack of snow

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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.

The Five Red Flags of Avalanche Danger any time of year include:  1) Recent/current avalanche activity  2) Whumpfing sounds or shooting cracks  3) Recent/current heavy snowfall  4) Strong winds transporting snow  5) Rapid warming or rain on snow.

 


 

    Weather and Current Conditions

    Weather Summary

    In Mt Shasta City this morning at 0500, we have cloudy skies with light rain, and a current temperature of 47 F degrees. 

    WEATHER STATION INFORMATION (0500hrs):

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

    Old Ski Bowl - 7,600 feet, the current temperature is 31 F. Snow on the ground totals 80 inches, with a trace of new snow and no settlement.  Temperatures have ranged from 29 F to 44 F.

    Gray Butte - 8,000 feet, the current temperature is 30 F. Temps have ranged from 28 F to 39 F. Winds have been primarily southwest averaging 12 mph with max gusts to 28 mph, SW.

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

    Castle Lake - 5,600 feet, the current temperature is 37 F. Temps have ranged from 34 F to 54 F. The Castle Lake area has very little snow left on the ground.

    Mt Eddy - 6,500 feet, the current temperature is 35 F. Temps have ranged from 31 F to 44 F in the last 24 hours. Current snow depth is 20 inches with no settlement.  Winds have been variable, 1-3 mph, with gusts to 11 mph, SSW.

    WEATHER SYNOPSIS: Light rain (snow at higher elevations) has begun to fall over the area as a cold front begins to move onshore.  A stream of moisture will continue to spread across the area with the heaviest precipitation amounts falling late this afternoon into this evening.  Showers will persist through tonight into Monday morning, then begin to tapper off by Monday afternoon.  Another surface low will push onshore following this recent system bringing the potential for another period of rain and snow Monday night into Tuesday morning.  High pressure returns on Wednesday bringing back warm temperatures and mostly clear skies.

    THIS SEASON PRECIPITATION: Since October 1st (the wet season) , we have received 30.84 inches of water, normal is 34.04 inches, putting us at 90% of normal. For the month of March, we sit at 0.68 inches of water, normal is 4.54, putting us at 15% of normal. For the year of 2015, we've received 11.32 inches water, normal is 18.83, equalling 60% of normal. 

     
    Snow Survey Results for March 2015 for the Sacramento, Shasta and Trinity Watersheds: 49% of normal with at average depth of 37 inches. Historic average for snow is 76.8 inches. Last year at this time we were 36% of normal. Similar years to this year are 1936, 1977, 1988, 1994.

    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.

    CURRENT CONDITIONS at Bunny Flat (6950 ft)
    0600 temperature: 31
    Max. temperature in the last 24 hours: 44
    Average wind direction during the last 24 hours: Southwest
    Average wind speed during the last 24 hours: 10-20 mph mi/hr
    Maximum wind gust in the last 24 hours: 28 mi/hr
    New snowfall in the last 24 hours: .05 inches
    Total snow depth: 80 inches

    Two Day Mountain Weather Forecast

    Produced in partnership with the Medford NWS

    For 7000 ft to 9000 ft
      Sunday
    (4 a.m. to 10 p.m.)
    Sunday Night
    (10 p.m. to 4 a.m.)
    Monday
    (4 a.m. to 10 p.m.)
    Weather Cloudy, rain and snow Cloudy, rain and snow becoming all snow after 11pm snow showers likely
    Temperature (°F) 36 30 31
    Wind (mi/hr) South 10-20 mph Southwest 10-15 mph Southwest 10-15 mph
    Precipitation SWE / Snowfall (in) / 2-3 inches / 3-5 inches / 1-2 inches
    For 9000 ft to 11000 ft
      Sunday Sunday Night Monday
    Weather Cloudy, snow Snow Snow showers
    Temperature (°F) 22 16 with wind chill values as low as -5 20
    Wind (mi/hr) Southwest 35-40 mph with higher gusts Southwest 2-4 inches West 30-35 mph
    Precipitation SWE / Snowfall (in) / 2-4 inches / 5-9 inches / 2-4 inches

    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.