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Avalanche Advisory for 2014-03-28 06:59:50
- EXPIRED ON March 29, 2014 @ 6:59 amPublished on March 28, 2014 @ 6:59 am
- Issued by Nick Meyers - Shasta-Trinity National Forest
Avalanche Problem 1: Wind Slab
Likelihood ?CertainVery LikelyLikelyPossible
Size ?HistoricVery LargeLarge
In the last 3 days, 8-13 inches of snow has fallen on our existing firm, melt/freeze spring snowpack. Winds blew primarily out of the West. Recently formed wind slabs at mid and upper elevations on Mt Shasta should be a concern today. Recent wind loading has allowed for wind slabs up to several feet thick to form near treeline and above treeline, especially on NE-E-SE aspects, but not limited to. Human triggered avalanches remain possible today on recently wind loaded slopes steeper than 35 degrees. In the more heavily wind loaded areas, avalanche size will easily be large enough to bury or injure a person. As we receive more precipitation this weekend in the form of snow on the mountain, this will add further stress to the snowpack and one should expect the avalanche danger to rise.
Avalanche Problem 2: Storm Slab
Likelihood ?CertainVery LikelyLikelyPossible
Size ?HistoricVery LargeLarge
Storm slabs may exist on all aspects and elevations. Weak layers will lie at density changes within the new storm snow. Slopes steeper than 35 degrees will be most prone to storm slab instabilites.
We are back into winter conditions on Mt Shasta after a spell of beautiful weather and fantastic spring skiing. Up to 1 foot of new snow has fallen over the week on the mountain. The weeks precipitation came in warmer and finished off cooler, leaving us with a right side up layering of new snow that seems to be well pasted to the old snow. Visibility was in and out yesterday and I was only able to make it to about 8,100 feet before whiteout conditions prevailed. My travels took me to all aspects around the Old Ski Bowl and Gray Butte area and was hard pressed to find any instability in the form of wind and/or storm slabs.
On Gray Butte, 7,500 feet, south facing - 35 degree slope, I found 18cm of new snow with numerous ECTX stability test results.
In the Old Ski Bowl at the weather station, 22cm of new snow fell with a total snow depth of 150cm.
On the shoulder of Green Butte, 8,079 ft., east facing - 38 degree slope, numerous ECTN12-15 Q3 @ 12cm down from top of new snow. About 24cm of new snow at this location...the bottom 12cm of new snow was 15% density and the top 12cm was 10% density.
The most new snow was found consistently on NE - E - SE slopes, as westerly winds prevailed over the last 5 days. A random east facing knoll in the Old Ski Bowl around 8,000 feet hosted 34cm of new snow. About half as much new snow will be found on other aspects.
All in all, lower to mid elevation slopes and all aspects indicated a stable snowpack. I was unable to propagate any instability at the old snow/new snow interface yesterday. That being said, one should have concern for additional snow and wind loading of the snowpack this weekend where wind and storm slabs have already developed. Weak layers could lie at density changes within the snowpack or the old/new snow layer.
For climbers, conditions have been excellent on all routes. With the recent new snow however, one might want to postpone your trip until melt/freeze snow conditions return. The season for climbing Mt Shasta is going to be shifted forward this year. On a normal year with ample snow on the ground, good climing conditions usually start in April and can go all the way into July sometimes. This year is not the case...the best conditions to climb Shasta this year will be NOW through April and potentially May. The extent of good climbing conditions will hinge on our Spring weather. More snow could potentially extend the season and warm days with shining sun will shorten it. While the mountain looks like it's got a thick blanket of snow on it, in reality there is only about 2-5 feet of snow on the ground, depending on aspect and elevation. Good climbing conditions, in general, means snow on the mountain. As the snow melts, rockfall increases and a climb of Shasta becomes more dangerous. All in all, sooner than later will be best for climbing Shasta. Check the climbing advisory on our webpage also!
PLEASE NOTE: Snow conditions on most routes are smooth and firm, especially in the AM hours. Conditions as such have lead to accidents due to slip/falls and failure to self arrest. A slip and fall on smooth, firm and sometimes icy snow can result in a slide for life on the steeper slopes of Mt Shasta. Self arrest skills with an ice axe and proper crampon use are essential for a safe climb. Do not under estimate the importance of proper knowledge and skills with your ice axe/crampons/self arrest techniques. Further, an avalanche beacon, shovel and probe are recommended for any climbers attempting Shasta currently. Lastly, with snow on mountain, the rockfall danger has been low. However, rime ice can plaster exposed rocks on Shasta this time of year. As the days warm, the rime ice will flake off and fall onto climbers below, especially on the Avalanche Gulch route. Ice is like a rock and a HELMET should always be worn.
Aerial photo of the South side of Mt Shasta, taken by local pilot Troy Bainbridge about 2 weeks ago.
While Northgate, Brewer Ck and Clear Ck trailheads are officially closed, the bathrooms are still open with packout bags inside, and one can still access the Mt Shasta Wilderness. However, your summit pass and wilderness permits must be purchased at McCloud or Mt Shasta Ranger Stations. NO DOGS are allowed in the Mt Shasta Wilderness OR Sierra Club Property. Thanks!
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 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.
Weather and Current Conditions
In Mt Shasta City this morning at 0500, we have cloudy skies and light rain falling with a current temperature of 42F.
On Mt Shasta (South Side) in the last 24 hours...
Old Ski Bowl - 7,600 feet. The Old Ski Bowl weather station has received 8 inches new snow since Tuesday the 25th. The current temperature is 27F with a low of 19F and a high of 30F. Total snow depth is 59 inches.
Gray Butte - 8,000 feet - The current temperature is 26F. Temps have ranged from a low of 19F to a high 28F. Winds have been westerly, averaging 15 mph with max gusts topping out at 28 mph from the west/northwest.
Castle Lake and Mt Eddy (West side of I-5)...
Castle Lake - 5,600 feet, the current temperature is 31F with a low of 25F and a high of 47F. Castle Lake has received trace of new snow over the week and has a current snowpack of 0-4 inches.
Mt Eddy - 6,500 feet, the current temperature is 30F with a low of 23F and a high of 37F. Mt Eddy has received 4-5 inches of new snow over the week and the current snow depth total is 19 inches. Winds have averaged 2 mph and southerly in nature, with gusts to 12 mph from the south/southeast.
THIS SEASON: Since September 1st , we have received 11.64 inches of water, normal is 35.60 inches, putting us at 32% of normal. For the year of 2014, Mt Shasta has received 8.82 inches of water with normal being 19.72 inches which puts us at 44% of normal. And lastly, for March we sit at 51% of normal, receiving 2.78 inches of water, normal is 5.43 inches.
The bottom line for today and the coming weekend weather is WET! Precipitation forecasts are still showing just about 2" of water for Mt Shasta City through Sunday. The heaviest precip will fall during the dark hours of tonight and early tomorrow morning. We should see a short, brief warming trend tomorrow which will keep snow levels at 6,000 to 7,000 feet. Temperatures will drop as we move into Sunday and that will help snow levels come down to 3,000 to 4,000 feet. Wind will be a factor with this weekends storm. Expect generally westerly winds above treeline to increase through Saturday. Wind speeds will likely hit 50-60 mph on the mid to upper elevations, in exposed areas.
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.
|Max. temperature in the last 24 hours:||30|
|Average wind direction during the last 24 hours:||Westerly|
|Average wind speed during the last 24 hours:||15 mi/hr|
|Maximum wind gust in the last 24 hours:||28 mi/hr|
|New snowfall in the last 24 hours:||1-3 inches|
|Total snow depth:||59" inches|
Two Day Mountain Weather Forecast
Produced in partnership with the Medford NWS
|For 7000 ft to 9000 ft|
(4 a.m. to 10 p.m.)
(10 p.m. to 4 a.m.)
(4 a.m. to 10 p.m.)
|Wind (mi/hr)||South/Southwest 15-25 mph in afternoon||South/Southwest 10-20 mph||South/Southwest 15-20 mph|
|Precipitation SWE / Snowfall (in)||/ 4-6||/ 5-9||/ 2-4|
|For 9000 ft to 11000 ft|
|Wind (mi/hr)||Southwest/West 25-35 mph this morning, increasing to 40-50 mph this afternoon||Southwest/West 4-8||Southwest/West 30-40 mph, decreasing|
|Precipitation SWE / Snowfall (in)||/ 4-8||/ 9-13||/ 3-5|