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Avalanche Advisory for 2017-03-14 06:35:59
- EXPIRED ON March 15, 2017 @ 6:35 amPublished on March 14, 2017 @ 6:35 am
- Issued by Andrew Kiefer - Mt Shasta Avalanche Center
Avalanche Problem 1: Loose Wet
Likelihood ?CertainVery LikelyLikelyPossible
Size ?HistoricVery LargeLarge
As snow surfaces thaw, wet loose avalanches will become a concern on E-SE-S-SW-W aspects, primarily near and below treeline. In addition, incoming solar radiation and warming temperature will melt rime ice formations in the alpine and create a falling ice hazard. Falling rime ice also has the potential to entrain unconsolidated surface snow on slopes below. Watch for roller balls and pinwheels as snow surfaces melt, and monitor changing boot and ski penetration. Be intentional with your timing in avalanche terrain, and avoid steep slopes that present wet and unconsolidated snow surfaces.
A loose wet avalanche is a release of unconsolidated snow or slush. It starts at a point and entrains snow as it moves downhill. A terrain trap such as a gully, cliff, or an abrupt slope transition can significantly magnify the consequences of being caught in a wet loose avalanche.
Sunshine and clear skies will continue this morning before a pattern shift in the weather begins this afternoon. Recent wet loose avalanche activity has been minimal, and the snowpack has responded well to the warm temperatures. Falling rime ice in the alpine currently presents the greatest objective hazard on Mount Shasta. Backcountry travelers who venture high on the mountain should be aware of rime covered rock overhead, especially as it warms up throughout the day.
Almost all of our remote weather stations have reported above freezing temperatures over the past 24 hours. High temperatures yesterday were in the upper 50’s F. South and southwest winds increased overnight, and likely have helped in solidifying/freezing snow surfaces by this morning.
The snowpack in the Castle Lake area is isothermal, and the upper snowpack has transitioned to corn on solar aspects. No recent avalanches were observed yesterday during a tour on the peaks above Castle Lake, and the snowpack surface handled the rapid warm up well. East and south facing aspects have delivered the most reliable and highest quality corn skiing recently, but by noon yesterday, boot penetration had increased to 20-25cm and the skiing became sloppy. North facing aspects had the most inconsistent snow surfaces. West facing aspects remained firm until noon. The timing of the morning thaw has been variable the past few days.
Weather and Current Conditions
Expect sunny skies this morning and increasing cloud cover in the afternoon. High temperatures at the 6000ft level will be near 60 degrees. Winds will blow out of the south and southwest and will steadily increase in speed over the next 24 hours. A low-pressure trough in the eastern Pacific will gradually move onshore tonight and tomorrow. Precipitation should begin early tomorrow morning, and will come in the form of both rain and snow with freezing levels near 8500ft. By Wednesday night, the advisory area should pick up a quarter inch of water, translating to 2-4 inches of snow above 9000ft.
In Mt Shasta City at 0500, we have a current temperature of 37 F.
On Mt Shasta (South Side) in the last 24 hours...
Sand Flat - 6750 ft, the current temperture is 35 degrees F. Temperatures have ranged from 30 F to 57 F. Snow on the ground totals 105 inches with no new snow and 1 inch of settlement.
Old Ski Bowl - 7,600ft. the current temperature is 41 degrees F. Temperatures have ranged from 37 F to 56 F. Snow on the ground totals 179 inches with no new snow and 2 inches of settlement.
Gray Butte - 8,000 feet, the current temperature is 42 degrees F. Temperatures have ranged from 42 F to 52 F. Winds have averaged 10-20 mph with gusts to 28 mph out of the west/northwest.
Mt Eddy Range (West side of Interstate-5)...
Castle Lake - 5,800 feet, the current temperature is 45 degrees F. Temperatures have ranged from 39 F to 59 F. Snow on the ground totals 106 inches with no new snow and 1 inch of settlement.
Mt Eddy - 6,500 feet, the current temperature is 42 degrees F. Temperatures have ranged from 35 F to 53 F. Snow on the ground measures 97 inches with no new snow and 2 inches of settlement. Winds have averaged 2-5 mph with gusts to 8 mph blowing out of the west/southwest.
THIS SEASON PRECIPITATION for MT SHASTA CITY: Since October 1st (the wet season), we have received 43.67 inches of water, normal is 32.59 inches, putting us at 134% of normal. For the month of March, we have received .36 inches of water, normal is 3.09 inches, which is 12% of normal. And finally for the year of 2017, we received 22.51 inches of water, normal is 17.38 inches, putting us at 130% 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.
|0600 temperature:||35 deg. F.|
|Max. temperature in the last 24 hours:||57 deg. F.|
|Average wind direction during the last 24 hours:||West/Northwest|
|Average wind speed during the last 24 hours:||5-10 mi/hr|
|Maximum wind gust in the last 24 hours:||25 mi/hr|
|New snowfall in the last 24 hours:||0 inches|
|Total snow depth:||105 inches|
Two Day Mountain Weather Forecast
Produced in partnership with the Medford NWS
|For 7000 ft to 9000 ft|
|Weather||Mostly Sunny||Mostly Cloudy||Rain and breezy. Chance of precipitation 90%|
|Temperatures||55 deg. F.||37 deg. F.||45 deg. F.|
|Wind speed||15 mph||21 mph||26-28 mph|
|Expected snowfall||0 in.||0 in.||0 in.|
|For 9000 ft to 11000 ft|
|Weather||Mostly Sunny and Windy||Mostly Cloudy and Windy||Snow and windy. Chance of precipitation 90%|
|Temperatures||32 deg. F.||27 deg. F.||29 deg. F.|
|Wind speed||41 mph||45-55 mph||60-70 mph|
|Expected snowfall||0 in.||0 in.||2-4 in.|