Avalanche Advisory
Advisory: Moab Area Mountains Issued by Eric Trenbeath for Saturday - December 24, 2016 - 6:58am
bottom line

Expect the avalanche danger to rise to CONSIDERABLE​ today in steep, upper elevation terrain where blustery winds and blowing snow will result in fresh drifts and the formation of new wind slabs. As the snow load increases, the danger for triggering a deeper, more dangerous persistent slab will also increase to CONSIDERABLE on slopes that face NW-N-E. For MODERATE danger, stick to lower and mid elevation sheltered terrain.




special announcement

Grand County was not able to get up and plow yesterday due to the priority of plowing public streets and county roads at lower elevations. Many cars made it up to the Geyser Pass Trailhead yesterday but 4wd is required. The Loop Road is also snow packed and icy, so be prepared for serious winter driving.

current conditions

You wouldn't have guessed it from the fog laden valley, but yesterday was sunny, clear, and calm in the mountains with 6-8" of fresh, dense snow. All of that is going to change today, and southerly winds have been on the increase since yesterday evening. Winds are currently averaging 20 mph with gusts into the 30's along ridge tops. They will continue to increase today, getting up into the 30-35 mph range with gusts as high as 60. 3-5" of snow is in the forecast today, with up to a foot or more possible through Christmas Day. The short of it translates to wild blustery conditions with blowing snow and a rising avalanche danger over the next 24 hours.

Dave Garcia was back on the scene yesterday and provided us with this excellent observation.

Storm totals and temperature in Gold Basin.(10,000')

Wind, temperature and humidity on Pre Laurel Peak.(11,700')

Snow totals, temperature and snow/water equivalent at the Geyser Pass Trailhead.(9600')

Things took a beating above tree line this week with southwesterly slopes like these near Pre-Laurel Peak getting scoured down to the rocks.

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

Strong, gusty winds, plenty of loose snow available for transport, and more snow in the forecast, all translate to drifting snow and the formation of new wind slabs. Avoid areas of recently deposited, wind drifted snow and look for tell tale signs of instability such as cracking in the snow surface. A triggered wind slab also has the potential to step down into a deeper persistent slab.

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

The snowpack structure is complex and poor in many areas. As this storm progresses, the likelihood for triggering a deep, persistent slab avalanche will increase. You are most likely to encounter this problem on steep, upper elevation slopes that face NW-NE-SE, but mid elevation slopes are not immune. Best bet is to keep your slope angle to around 30 degrees or less in these areas, and avoid slopes that appear to be drifted.

weather

Today

Snow likely, mainly after 9am. Mostly cloudy, with a high near 27. Windy, with a south wind 30 to 35 mph, with gusts as high as 60 mph. Chance of precipitation is 60%. Total daytime snow accumulation of 3 to 5 inches possible.

Tonight

Snow. Low around 7. Windy, with a southwest wind 25 to 35 mph, with gusts as high as 55 mph. Chance of precipitation is 100%. New snow accumulation of 8 to 12 inches possible.

Christmas Day

Snow. High near 15. Wind chill values as low as -15. Breezy, with a west southwest wind around 20 mph, with gusts as high as 35 mph. Chance of precipitation is 80%. New snow accumulation of 3 to 7 inches possible.

Sunday Night

A 30 percent chance of snow, mainly before 11pm. Mostly cloudy, then gradually becoming mostly clear, with a low around 3. Wind chill values as low as -10. Southwest wind 10 to 15 mph.

Monday

Sunny, with a high near 16. Southwest wind around 10 mph becoming west northwest in the afternoon.