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Avalanche Advisory for 2015-03-13 07:00:58

  • EXPIRED ON March 14, 2015 @ 7:00 am
    Published on March 13, 2015 @ 7:00 am
  • Issued by Nick Meyers - Shasta-Trinity National Forest

The avalanche danger is LOW for all elevations and aspects.

Some shallow, small, isolated wind deposits or loose wet instabilities might exist on some extreme terrain features and slopes steeper than 35 degrees. They will likely not entrain enough snow to be of concern. Use normal caution.

Climbers should be heads up for ice fall, "slide for life" conditions and very high winds (southwest) this weekend.

 

 

 

 

 

 

 

 

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: Loose Wet

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Isolated features in steep terrain near and above treeline may see human triggered loose wet snow instabilities, roller balls, and pinwheels on mainly south and southeast aspects during the warmest parts of the day.  While they likely will not entrain enough snow to bury a somebody, they could potentially knock a person off their feet and push them into undesirable terrain.

 

Recent Observations

Perhaps the idea of "Miracle March" not exactly formulating has some of you contracting Recreational Stress Syndrome. Symptoms include confusion, anxiousness, inability to focus, bailing on adventure plans for another plan with one or more partners, and multiple activity days resulting in poor family life, exhaustion. Naturally, we wish we were wallowing in powder snow, but we're not. That said, there is a plenthora of recreational opportunities available in the area including... skiing on a little bit of fresh, new snow!

The mountain received a couple inches of new snow with very little wind on 3-11-15, on top of our 85 inch rock solid base. It's always a pleasure when we get a storm without much wind. The storm placed a perfect, fresh, white satin blanket of medium density snow on top of our old snowpack and created some very smooth surface conditions. Snow levels with this storm were generally above 8,000 feet. From Bunny Flat to treeline, a skiff of snow was recorded and it wasn't until near and above treeline areas that measurable snow was encountered.

A fairly consistent 7 to 15 cm (3-6 in) of new snow deposited itself on the slopes of Shasta. Yesterday was a warm one and a few small surface instabilities were noted in Powder and Sun Bowl areas in the form of roller balls (8,000 to 9,000 feet, southerly facing). Snow on the trees above 8,000 feet also melted off also confirming warming. Stability tests indicated good bonding between old/new snow layers and overall new snow accumulation did not provide enough material to form significant slabs on top of old snow surfaces. That said, one may find a few small, shallow wind deposited drifts up high on the mountain near ridge lines and/or be able to trigger small loose wet snow instabilities like roller balls, pinwheels and isolated loose wet snow sluffs on steep sun-exposed aspects. Overall, LOW danger exists and normal caution is advised. 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! 

Photos below: 

A look up into Avalanche Gulch from the top of Green Butte on 3-12-15, Casaval Ridge on left skyline, Green Butte to Sargents Ridges middle, Old Ski Bowl left. [Photo: H. Meyers}
Smooth snow heading up Broadway (Lower Green Butte Ridge) on 3-12-15! [Photo: H Meyers]

 

For folks that plan on climbing Mt. Shasta:  Route conditions on Casaval Ridge, Sargents Ridge, and Avalanche Gulch are currently good.  That being said, there are some objective hazards to be noted.  Snow surfaces will be firm and smooth in the early morning hours and will make for "slide for life" conditions.  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, trail conditions are firm and getting thin with some tree debris on snow surface. 

Pilgrim Creek Snowmobile Park: OPEN, however due to lack of low elevation snow, one must drive up the road several miles before enough snow is encountered. One CANNOT DRIVE over Military Pass. Snowmobiling is not recommended due to low snow depths.

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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 mostly clear skies and a current temperature of 44 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 50 F. Snow on the ground totals 85 inches with 2 inches settlement. Temperatures in the last 24 hours have ranged from 25 F to 50 F. Over the week, on 3-11-15, we saw a small storm that gave us 2-3 inches of new snow (.53 inches water) recorded at this station.

    Gray Butte - 8,000 feet, The current temperature is 49 F and temps have ranged from 27 F to 50 F in the last 24 hours. Winds have been primarily ENE in direction, averaging 10-20 mph with max gusts to 42 mph, ENE.

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

    Castle Lake - 5,600 feet, the current temperature is 42 F. Temps have ranged from 33 F to 51 F in the last 24 hours. The Castle Lake area has a patchy 6-8 inches of snow on the ground and no new snow during this last storm. 

    Mt Eddy - 6,500 feet, the current temperature is 38 F. Temps have ranged from 30 F to 47 F in the last 24 hours. Current snow depth is 27 inches with 1 inch settlement.  Winds have averaged 3 mph SW, with gusts to 8 mph, east.

    WEATHER SYNOPSIS: Today should be a pretty nice day albeit with gusty winds, and daytime temps well above normal. For the weekend, we will see gradually increasing clouds and higher wind speeds as a subtropical storm moves into the area. This storm will be short lived and is expected to bring a predicted .75 inches of water by the end of storm Monday. Southwest/west winds will start to pick up Saturday, with highest wind speeds on Sunday. I wouldn't be surprised to see mid and upper mountain wind speeds at 40-50 mph with gusts higher. While we are excited for any kind of winter storm, the bummer for this one is the warm temps keeping snow levels high. Temperature models indicate freezing levels to hover between 8,000 and 9,000 feet. Near and above treeline areas should get several inches of snow, however below treeline down to Bunny Flat could be wet. Next week is predicted to be mostly dry.

    THIS SEASON PRECIPITATION: Since October 1st (the wet season) , we have received 30.25 inches of water, normal is 32.37inches, putting us at 93% of normal. For the month of March, we sit at 0.09 inches of water, normal is 2.87, putting us at 3% of normal. For the year of 2015, we've received 10.73 inches water, normal is 17.16, equalling 62% 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.

    CURRENT CONDITIONS at Bunny Flat (6950 ft)
    0600 temperature: 50
    Max. temperature in the last 24 hours: 50
    Average wind direction during the last 24 hours: Easterly
    Average wind speed during the last 24 hours: 10-20 mph mi/hr
    Maximum wind gust in the last 24 hours: 42 mi/hr
    New snowfall in the last 24 hours: 0 inches
    Total snow depth: 85 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 Mostly sunny Increasing clouds Storm moving in, chance of rain during the day, rain likely afternoon/evening
    Temperature (°F) 58 39 49
    Wind (mi/hr) Southeast 5-15 mph South 10-20 mph South/southwest 15-20 mph
    Precipitation SWE / Snowfall (in) / 0 / 0 / 0
    For 9000 ft to 11000 ft
      Friday Friday Night Saturday
    Weather Mostly sunny Increasing clouds Storm moving in, chance of snow during the day, snow likely at night
    Temperature (°F) 53 33 44
    Wind (mi/hr) South/southwest 20-30 mph with gusts into the 40's South/southwest 0 Southwest 30-40 mph with gusts into the 50's and 60's
    Precipitation SWE / Snowfall (in) / 0 / 0 / 0-1

    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.