Avalanche Advisory for 2016-02-23 06:31:12

Observations made yesterday are limited to information recorded by our four weather stations, and what was visible above treeline.  Wind speeds recorded at Grey Butte weather station were light at 10-15 mph.  Much stronger winds, however, were quite evident at higher elevations due to banners of snow billowing off of ridge tops above the West Face and the Red Banks.  Wind slab formations are likely, and areas of concern are outlined below.

On Sunday, an MSAC forecaster ventured out to the east side of our forecast area to make observations of the snowpack conditions.  The only evidence of snow instabilities were some roller balls on east to south facing slopes around mid-day when temperatures were at their warmest.  Winds increased in the afternoon coming out of the North, and d high clouds began to stream over the area.  Decent powder snow was still present on more northerly, shaded aspects making for good skiing/riding conditions.  Snowmobilers had "high marked" and traversed on leeward, wind loaded slopes with no reaction from the snowpack.  A snow study pit was dug, and a full pit profile taken (see graph below) on a north aspect at 7,500 feet with a slope angle of 32 degrees.  An extended column test was performed resulting in a score of ECTX.  A compression test was also performed resulting in a score of CT23 Q2 at 30 cm deep at a change in density.  The forecaster's was that overall stable conditions exist.

For today, our main concern for snow instabilities will continue to be for loose wet snow avalanches, roller balls, pinwheels, and point release slough slides on E-SE-S-SW-W aspects during the warmest parts of the day.  Daytime warming over the next few days will be significant with unseasonably warm temperatures.  Aspects where loose wet slides are common on Mt. Shasta are the SE aspect of Casaval Ridge that drops into Avalanche Gulch, SE aspects in Sun Bowl and Powder Bowl, and Right Peak in the Castle Lake area.  Strong northerly winds that affected elevations of 10,000 feet and above have developed new wind slab formations in pockets around rock outcroppings along and just below ridge tops (think Casaval Ridge), the tops of chutes and couloirs, and non-typical spots such as mid-slope depressions and gullies.  Careful snowpack evaluation, and conservative decision making will be essential.  Caution should be taken when choosing one's route of travel, especially in the afternoon hours due to loose wet instabilities.  While not much of a problem themselves, they can entrain enough snow to be a hazard to backcountry travelers.  They could knock a person off of their fee, and push them over a cliff band, through tight trees, or into a terrain trap where enough snow could collect to fully bury a person.

Full Pit Profile from the east side of the forecast area on 2-21-2016:

Photo of Grey Butte Pit Profile on 2-20-2016 highlighting the most recent snow layers:

View of Old Ski Bowl, South side of Mt. Shasta, from the top of Grey Butte:

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LOCAL AREA ROAD, NORDIC, AND SNOWMOBILE PARK STATUS:

The Sand Flat cross country ski trails are in good shape and ready for your cross country skis and snow shoes.  These are backcountry routes marked with blue diamonds on trees.  Trails are not groomed.  Snow shoers, please blaze a parallel trail to cross country skiers staying out of the skin track.  These trails can be accessed via the Everett Memorial Highway.  Thank you, and enjoy!

The Mt. Shasta Nordic Center is open! These beautiful, groomed trails can be accessed via the Ski Park Highway. http://www.mtshastanordic.org

The Pilgrim Creek & Deer Mountain Snowmobile Parks are open!  Trails have not been groomed in the past week and a half due to warm temperatures.  Head to our "Education" tab on our website and find the snowmobile section for trail information, grooming status, and other sledder resources.

The Castle Lake Road is plowed to the lake. The Everett Memorial Highway is plowed to Bunny Flat.

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