The Mt. Shasta Avalanche Center - US Forest Service 

Free Avalanche Awareness presentations this week in the SF Bay Area:  Tuesday, 2/9, Berkeley REI 7 pm, Wednesday, 2/10 Corte Madera REI, Thursday, 2/11, Mnt. View REI

Update, Monday, 2/8/10 @10 am:   While things are starting to settle down, we have had many natural avalanches and human triggered avalanches over the last 5 days, especially last Friday (2/5) and Saturday (2/6).  A natural from last Friday is still visible in Wagon Bowl on Mt. Eddy with high marks around it.  Most of these occurred between 6-8000 ft.  Sensitive areas still exist, especially above tree line and on all steep slopes.  Before you drop in, review the terrain, weather and snow pack and think about the consequences. The County has worked again on the Castle Lake road and it is open to the Vista Pt. above Methodist (1.5 mi. below lake).  They have run into difficulties on the Everitt at Windy Point (0.75 mi below Bunny Flat) due to deep and dense wind drifts - still working on it and remains closed at the gate.

Avalanche Advisory issued Sunday February 7, 2010 at 7:05 am  

By Eric White  & Dan Towner                     

The Bottom Line:

Avalanche Danger Rating* for today:

Where:  MODERATE avalanche danger especially on slopes greater than 35 degrees.  MODERATE means than natural avalanches are unlikely and human triggered avalanches are possible

Primary Concern:   soft slabs in the recent 2 ft. of new snow above 6000 ft.

Secondary Concerns:   wind slabs near and above tree line on N aspects

Size and Character:  small to medium sized slab avalanches with both hard/wind slabs and soft slabs

Sensitivity to Triggering:  Decreasing due to warm temperatures and settlement, but could still be triggered by an individual or machine.

Confidence in today's Forecast:  Moderate.  Field data is minimal at mid and upper elevations.

Trend over next 4 days:  Unsettled weather and changing temperatures will allow the avalanche danger to fluctuate slightly this week.  Check our weather stations for changes in precipitation, wind and temperature.  Check the National Weather Service for the most recent forecast information. 

The Details:

This Season:  Moderate to strong El Nino conditions exist in the equatorial Pacific.  Climatologists predict a 33% chance of above normal precipitation for much of northern California over the next 3 months, and higher chances of above normal precipitation in central and southern California.  Since September 1, our precipitation is 134% of normal in Mt. Shasta City (NWS ASOS station).  The Martin Luther King Jr. storm was the biggest of the season with several days setting precipitation records.  From January 17 to January 26, we received 12.80 inches of water and 9-10 ft. of snow at mid elevations.  Ice and very wet snow during this storm caused a plethora of snapping trees and power lines in town, closing roads and brought a state of emergency to Mt. Shasta City.  Since 1948, this was the 3rd wettest January on record.  Snow survey results at the beginning of February in the Mt. Shasta area show the snow pack at 143% of normal.  

Weather Observations at 5 am:  We have mostly clear skies in town this morning with patchy fog, and light NW winds.  It is currently 37F in Mt. Shasta City and the barometric pressure is on the rise.  We received .21 inches of rain over the last 24 hours.   On Mt. Shasta:  The current temperature at the Old Ski Bowl(7,600') is 20F and yesterdays high was 31F. We received 2 inches of new snow in the past 24 hours, with 3 inches of settlement and the current snow depth is 147 inches.  At Grey Butte(8,000') the current temperature is 21F and  yesterdays high was 32F.  Winds have been generally out of the SSE, averaging 7 mph, but gusting to 21 mph.    Castle/Mt. Eddy:   Temperatures were between 27-36F at Castle Lake, with 3 inches of new snow, 2 inches of settlement and 140 inches on the ground.  On Mt Eddy, temperatures were between 27-33F, with 3 inches of new snow, 3 inches of settlement and 118 inches on the ground.  

Weather Forecast:  High pressure will keep us dry on Sunday aside from some fog/mist in the first part of the day.  Unsettled weather will be with us this week as the jet stream conveyor belt brings storms across the Pacific to the West coast.  Occasional splits in the jet will push the bulk of the weather north of our area.  A stronger storm is expected at the end of the week.  Today:  Low level clouds with mist/rime to light snow will be possible and the snow level will be around 4000 to 4500 t. in the morning, then becoming partly cloudy.  Temperatures below tree line will warm to the mid to upper 30's, while near and above tree line temperatures will warm to the mid 20's to mid 30's.  Winds will be from the N and NE and remain fairly light at most elevations with light NW winds on the upper mountain.  Next 4 days:  Some uncertainty overall, but it looks like a cold storm will arrive Monday night and into Tuesday with 3-5 inches of snow possible and the snow level dropping below town to 2500 ft.   Wednesday looks like a break with decreasing showers to dry weather and temperatures warming.  Another storm will begin arriving on Thursday and will bring stronger southerly winds to mid and upper elevations on the mountain.  Extended:  It looks like mild weather next weekend with another storm arriving Monday (2/15).

Snow Pack:    Just a trace of new snow at most mid elevation areas overnight, with temperatures generally a few degrees cooler than yesterday morning.  Cooler overnight temperatures should help the snowpack to gain strength.  We have now had 24-36 hours since our last significant snowfall, which has allowed the snow to settle and the bonds to strengthen; but keep in mind that the last storm added a significant load.  If we get significant solar input today, southerly aspects could become especially sensitive at the upper elevations.  Caution would still be advised, especially on steeper (30- 35 degree) sun warmed aspects.  Later today, N winds begin to develop and possibly move snow to S aspects at the upper elevations, although they don't look strong.

Link to video showing Rutschblock stability test 2/5/10

Link to video showing Rutschblock stability test 1/14/10

Link to video showing stability test 1/9/10 

Link to video showing the 1/2/10 Pelican Butte avalanche accident (recovered alive) 

Link to short video #1 from 1/2/10 showing wind loading Mt. Shasta

Link to short video #2 from 1/2/10 with Rutschblock test results, Mt. Shasta

Link to short video showing shallow snow pack and facet layer on ground, 12/24/09.

Some Important Thoughts:  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 at midnight tonight.  As always, use safe travel practices:  travel with a partner, travel one at a time in suspect areas, go from one island of safety to another, choose safe routes, wear a transceiver, carry a shovel and probe, and know how to use your gear!

Pilgrim Creek Snowmobile Park:  Groomed Pilgrim to Deer Mnt. on 2/5.  Groomed Trout creek 2/4 with some track grooming and some tillered.  Watch for lots of debris. 

MSAC Upcoming Events:

Go to "Photos/Avy Shots" for photos of recent avalanches.  

Please report weather and snow observations- you could help save a life:  (530)926-9614  Thanks!