Avalanche Advisory
Advisory: Moab Area Mountains Issued by Eric Trenbeath for Tuesday - December 15, 2015 - 6:14am
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Today there is a CONSIDERABLE avalanche danger on all aspects on slopes steeper than 35 degrees. This means that human triggered avalanches are likely and natural avalanches are possible. Only experienced backcountry travelers, with excellent route findings skills, should venture into areas of avalanche terrain today.




special announcement

The Utah Avalanche Center-Moab will be presenting a free Know Before You Go avalanche awareness presentation at the Grand County Library on Thursday, December 17 at 6:30 p.m. Call the Manti-La Sal National Forest office at 435-259-7155 for more information.

current conditions

Well that turned out to be a bona fide dump depositing 2' or more of extremely low density snow in the mountains. The first 6" came in strong and early yesterday morning. Then around 4:00 pm things really started getting after it with snow fall rates at times coming in at 3" an hour before tapering off a little after midnight. Southerly winds early in the storm blew in the 15 - 20 mph range, but since about 2:00 pm yesterday they have been mostly in the single digits shifting to west to more westerly. Expect them to increase and shift to northwesterly later today.

It is a wintry 12 degrees at the Geyser Pass Trailhead this morning.

Winds, temperature and humidity on Pre-Laurel Peak

New snow totals, temperature and humidity in Gold Basin

Total snow depth and temperature at Geyser Pass Trailhead



recent activity

Avalanche Problem 1
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

The new snow came in perfectly. It got lighter and lighter as it stacked up, and beyond the initial 6", it came in with virtually no wind. But it is still a lot of snow. And I think that before it settles out, the probability for getting it to slide is considerable on all aspects, on slopes steeper than 35 degrees. In most cases, slides may act more like loose snow sluffs, but there may be areas where the snow has a more cohesive slab like property, especially as the day progresses and winds begin to increase. Slides triggered within the new snow also have the potential to step down into older, weak layers producing a larger and more dangerous avalanche. Today is a very good day to scale it back, stay off of, and out from under steep slopes until the new snow has had time to stabilize.

Avalanche Problem 2
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

We've begin to add straw to the proverbial camel's back with this storm though I don't think overall water weight has been enough to tip the scales and trigger a natural, persistent slab avalanche cycle. It is however, a tenuous balance, and I am certain that the added weight of skier or rider could trigger a persistent slab on a buried weak layer with significant consequences. In short, we've entered a period where it is time to avoid any slope 35 degrees or more in steepness that faces the north half of the compass.

weather

The storm is slowly moving eastward and as the flow shifts to northwest, we will see drier and colder air though snow showers are likely to linger into tomorrow with another 2-4" possible today. Northwest winds will be on the increase, blowing from 10-20 mph, and it is going to be cold. High temps at 10,000' will be around 11 degrees, but with wind chill it will feel like minus 15.

Tuesday

Snow. High near 11. Wind chill values as low as -15. Blustery, with a northwest wind 10 to 20 mph. Chance of precipitation is 80%. New snow accumulation of 2 to 4 inches possible.

Tuesday Night

A 50 percent chance of snow, mainly before 4am. Mostly cloudy, with a low around 8. Northwest wind 5 to 10 mph. New snow accumulation of less than one inch possible.

Wednesday

A 10 percent chance of snow before 8am. Mostly sunny, with a high near 13. Northwest wind around 10 mph, with gusts as high as 20 mph.

Wednesday Night

Partly cloudy, with a low around 1. West northwest wind 5 to 10 mph, with gusts as high as 20 mph.

Thursday

Partly sunny, with a high near 13.

general announcements

Plow crews will most likely not make it to the Geyser Pass Trailhead today as they will busy digging out down in Monticello. Expect to find a foot or more of snow on the road. The Loop road itself will likely be pretty sporty as well, though Grand County will likely get up there fairly early. 

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This information does not apply to developed ski areas or highways where avalanche control is normally done.  This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always exist.