Avalanche Advisory for 2015-03-27 07:01:02

A set of two brief storms earlier in the week on Monday and Tuesday brought a fresh coating of snow to Mount Shasta.  Up to 9+ inches fell then was transported by moderate to strong SW-W-NW winds scouring ridge tops and roll overs, and depositing on S-SE-E-NE aspects.  The storms were followed on Wednesday and Thursday by steadily increasing temperatures and sunny skies.  A record high temperature of 77 F was set in Mt. Shasta City on Thursday, breaking the old record by 4 degrees!  Today is forecast to be warm as well, but a few degrees cooler than yesterday.  Clouds will begin to build during the day with a slight chance of precipitation and possibly even thunderstorms this evening.  Winds will be out of the SW increasing as a cold front approaches then calming later tonight.  Winds are forecast to be breezy at the upper elevations of the mountain (above 9,500 feet) with speeds of 30-40 mph with higher gusts.

Observations reported from the mountain yesterday revealed some loose wet snow slide activity occurring on the SSE aspect of Casval Ridge that drops into Avalanche Gulch.  Starting zones for these slides was about 10,000-10,200 feet (photo below).  There will be the right conditions for similar instabilities today, especially in the warm afternoon hours.  Be cautious skiing or traversing along S-SE-E slopes later in the day.  These types of slides are typically not dangerous themselves, but they could knock one off their feet and push them into undesirable terrain.  Where snow had been scoured by winds down to the old snow surface, corn snow could be found.  Where the new snow has been deposited it has yet to fully transition via melt/freeze cycle into corn snow conditions.  An individual who skied Powder Bowl yesterday reported that the top half of the bowl that had been wind scoured was good corn snow. Half way down the slope the snow then transitioned into "manky"  and thick conditions.  No loose wet snow instabilities were reported in Powder Bowl/Sun Bowl area.   

Photos:
Top-Group break on ski descent along edge of Avalanche Gulch proper (3/23/2015) - Photo: Jon Dove

Bottom-Loose wet snow slides off the SSE aspect of Casaval ridge. Photo taken from 50/50 flat (3/26/2015) - Photo: Tim Dobbins

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 snow conditions will be variable as one will encounter areas that have been scoured down to the old snow surface and areas where snow from Monday and Tuesday has been deposited.  The areas of newer snow coverage have yet to fully make the transitions into corn snow.   Ice fall from rime ice that has built up on the Red Banks and other rock outcroppings will be 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).

Snowpack:  If 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’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.