You are here
Avalanche Advisory for 2018-01-11 06:26:50
- EXPIRED ON January 12, 2018 @ 6:26 amPublished on January 11, 2018 @ 6:26 am
- Issued by Nick Meyers - Shasta-Trinity National Forest
Avalanche Problem 1: Wind Slab
Likelihood ?CertainVery LikelyLikelyPossible
Size ?HistoricVery LargeLarge
Strong winds were transporting snow above 9000 ft yesterday on Mount Shasta. Wind loading is likely on N-NE-E-SE-S aspects. LOW avalanche danger does not mean NO avalanche danger. Monitor changing conditions if ascending above 9000 ft. Look for cornice formation and shooting cracks in drifted snow as evidence of the wind slab problem. If in doubt, avoid convex slopes greater than 35 degrees. Look at connected terrain and consider the consequences of being carried down hill by a small avalanche.
The snowpack below 9000 ft is locked up tight. Above, the wind slab problem is a small concern, but one to take seriously. The rime ice plastered on the crags of ridges continues to be a hazard. Warming temperatures will cause this ice to dislodge and plummet down upon skiers and climbers in the coming days. Wear a helmet. Hard chunks of ice can function just like a rock.
Mt Shasta is the only zone within the forecast area that holds a usable snowpack for winter recreation at this time. Castle Lake and The Eddy Mountains as well as much of the areas east of Mt Shasta are snow free or very thin.
Continued trouble shooting on the Ash Creek Butte weather station brought us out to the east side yesterday. Pilgrim Creek Snowmobile Park is still snowless. One is able to drive all the way to the Brewer Creek trailhead turnoff, off Military Pass road, and beyond with a good 4WD vehicle (muddy). Approximately 1 inch (2.5cm) new snow was on roadway at this point. Up on the Ash Creek Loop road (snowmobiles), a tad more new snow was observed, 2-3 inches (5-7cm). Patches of bare road existed in some areas. We don't advise riding out here currently. Winds aloft could be heard below treeline. Near and above treeline, gusty winds were blasting all day, 25-35 mph out of the west/northwest. Giant plumes of blowing snow were visible above 9,000 feet on Mt Shasta through a few brief doughnut holes in the clouds. The minimal amount of new snow was too moist below and near treeline to experience wind transport. Some slopes held a thin zipper crust. Mostly cloudy skies and low fog was the trend for the day. We did not observe any signs of instability or recent avalanches in the Ash Creek Butte area. We were not able to sight any recent crown lines on the east side of Mt Shasta either. Temperatures have warmed a bit this morning and daytime highs will be even warmer this weekend.
Weather and Current Conditions
The second of two weak frontal systems will move across the area today bringing a touch of precipitation. We could see up to a tenth of an inch of water. Temperatures have warmed and snow levels will hover near 7,100 feet. Most notable are high winds out of the west, near and above treeline. Steady speeds of 35 mph with gusts up to 50 mph are expected, especially in exposed areas, along ridge lines and the upper mountain. Friday, weather will begin to clear and sunny skies will commence the weekend as a ridge of high pressure sets up, bringing warmer temps. Next week, everyone is getting excited from murmurs of wet, unsettled weather lasting through the week and perhaps beyond. Wax'em and gas'em...we are getting excited too.
THIS SEASON PRECIPITATION for MT SHASTA CITY: Since October 1st (the wet season), we have received 7.81 inches of water, normal is 17.60 inches, putting us at 44% of normal. For the month of January and 2018, we have received 1.98 inches of water, normal is 2.39 inches, which is 82% of normal.
Always check the weather before you attempt to climb Mount 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 (mi/hr)||Snow (in)||Comments|
|Cur||Min||Max||Avg||Avg||Max Gust||Dir||Depth||New||Water Equivalent||Settlement|
|Mt. Shasta City (3540 ft)||41||36||44||40||1||N|
|Sand Flat (6750 ft)||33||27||36||33||11||0||0||1|
|Ski Bowl (7600 ft)||33||23||36||32||24||0||0||0|
|Gray Butte (8000 ft)||31||22||36||30||24||49||NW|
|Castle Lake (5870 ft)||38||28||40||35||0||0||0|
|Mount Eddy (6509 ft)||38||26||39||33||2||11||WSW||0||0||0|
|Ash Creek Bowl (7250 ft)||Station down|
|Ash Creek Ridge (7895 ft)||Station down|
Two Day Mountain Weather Forecast
Produced in partnership with the Medford NWS
|For 7000 ft to 9000 ft|
|Weather||Mostly cloudy with a 30% chance of snow.||Mostly cloudy with a 30% chance of rain and snow showers||Mostly cloudy with a 20% chance of rain and snow showers in AM, then partly cloudy in PM.|
|Wind Speed (mi/hr)||10-15 mph||10-15 mph||0-5 mph|
|Expected Snowfall (in)||<.5||<.5||0|
|For 9000 ft to 11000 ft|
|Weather||Mostly cloudy, 60% chance of snow, mainly after 10am, windy||50% chance of snow showers, mostly cloudy, windy||Chance of snow showers in AM, clearing to partly cloudy, windy|
|Wind Speed (mi/hr)||35-45 mph||40-50 mph||20-30 mph|
|Expected Snowfall (in)||1-2||1-2||0|