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Avalanche Advisory for 2017-12-30 06:06:56
- EXPIRED ON December 31, 2017 @ 6:06 amPublished on December 30, 2017 @ 6:06 am
- Issued by Nick Meyers - Shasta-Trinity National Forest
Avalanche Problem 1: Normal Caution
Likelihood ?CertainVery LikelyLikelyPossible
Size ?HistoricVery LargeLarge
Normal caution is advised. The firm, icy, and thin snowpack continues to create backcountry travel hazards. Moving through steep terrain above treeline is challenging and dangerous. Arresting a fall in these conditions would be difficult. Watch out for rocks. Low angle slopes with smooth ground cover offer the best skiing and riding conditions.
- Ski and ride one at a time in avalanche terrain.
- Don’t regroup in run-out zones.
- Avalanche rescue skills are always essential when you travel in avalanche terrain.
The broken record is badly broken. While no day is ever the same, the snow and weather have stayed close. A re-cap of our season thus far: October and November storms laid a shallow snowpack at high elevations on Mount Shasta. During Thanksgiving week, it rained up to 10,000ft. This rain event was followed by cold and clear weather which capped the snow surface at 7,000ft and above with a crust, while below, it eliminated any existing snow on the ground. We have had two small storm events this December totaling 10 inches of snow and less than 1 inch of water. Otherwise, high pressure has dominated our weather pattern. Precipitation is well below average, and a large portion of our advisory area is free of snow. Mt Shasta and Ash Creek Butte are the only areas with a (barely) usable snowpack. A warm storm system with modest precipitation is not expected until the first week of January. This weekend will be mostly sunny and westerly winds should die off by Sunday.
The snowline slowly creeps upward. Very little coverage exists below 6,500ft. The height of snow ranges from 30-100cm between 6,500-9,500ft. The rain crust that formed on Thanksgiving continues to lock up the lower snowpack. This slick, icy layer is the primary snow surface near and above treeline. North and east aspects below treeline, 20-25cm of recycled powder (the December 3rd and December 20th storms) exists at the snow surface. South and some west aspects, near and above treeline, patches of corn snow can be found. Snowpack stability is very good throughout the advisory area. Rocks, down trees, small tree tops and bushes are widespread.
Weather and Current Conditions
A weak warm front is stetched across the forecast area this morning with Mt Shasta out of it's main grip. A few light showers might be seen this morning on the mountain with little to no accumulation. Dry air will descend over the area today, skies will clear and the strong westerly winds will die down above treeline. High temps won't be as warm in most places. The short term forecast is uneventful. Chances of precipitation increase later in the first week of January. At this point, conflicting weather models suggest meager precip amounts and high snow levels...not exactly music to our ears. In a couple days, we will have a better idea on the details.
CLICK HERE for information from the NOAA Climate Prediction Center
THIS SEASON PRECIPITATION for MT SHASTA CITY: Since October 1st (the wet season), we have received 5.83 inches of water, normal is 14.70 inches, putting us at 39% of normal. For the month of December, we have received .29 inches of water, normal is 7.34 inches, which is 3% of normal. And finally for the year of 2017, we received 44.82 inches of water, normal is 42.70 inches, putting us at 104% 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.
24 Hour Weather Station Data @ 5:00 AM
|Weather Station||Temp (°F)||Wind (mph)||Snow (in)||Comments|
|Cur||Min||Max||Avg||Avg||Max Gust||Dir||Depth||New||Water Equivalent||Settlement|
|Mt. Shasta City (3540')||26||26||56||35||1||N|
|Sand Flat (6750')||38||32||49||39||15||0||0||0|
|Ski Bowl (7600')||39||35||49||41||19||0||0||0|
|Grey Butte (8000')||35||33||44||39||20||43||WNW|
|Castle Lake (5870')||43||40||49||44||9||0||0||0|
|Mount Eddy (6509')||39||37||53||44||2||7||WSW||11||0||0|
|Ash Creek Bowl (7250')||station down|
|Ash Creek Ridge (7895')||station down|
Two Day Mountain Weather Forecast
|For 7000 ft. to 9000 ft.|
|Weather||Chance of showers before 10am, otherwise clearing, partly sunny||Partly cloudy||Mostly sunny|
|Temperatures||47 deg. F.||35 deg. F.||47 deg. F.|
|Wind speed||5-10 mph||5 mph||0-5 mph|
|Expected snowfall||0 in.||0 in.||0 in.|
|For 9000 ft. to 11000 ft.|
|Weather||Chance of showers before 10am, otherwise clearing, partly sunny, windy||Partly cloudy, windy||Mostly sunny|
|Temperatures||33 deg. F.||33 deg. F.||34 deg. F.|
|Wind speed||30-40 mph, gusts higher||15-20 mph||5-10 mph|
|Expected snowfall||0 in.||0 in.||0 in.|