Avalanche Advisory
Advisory: Moab Area Mountains Issued by Eric Trenbeath for Wednesday - December 9, 2015 - 7:04am
bottom line

The avalanche danger is generally LOW, but there still may be isolated areas where it is possible to trigger a persistent slab avalanche, primarily on steep, upper elevation slopes that face the north half of the compass. Suspect slopes with more radical terrain and distinctive terrain features such as gullies, rock bands, or convex break overs.




current conditions

It's another balmy morning up there, 34 degrees at the Geyser Pass Trailhead, and 26 on top of Pre Laurel Peak. Winds are averaging 15 mph along ridge tops with gusts into the low 20's. The snow surface is what one would expect after so long without any new snow. It's a mixed bag of conditions with a variety of sun and wind crusts though soft snow can still be found on shady, sheltered aspects. In my travels I have also noticed that the pack is beginning to lose some of it's supportability, particularly on shady, wooded slopes below tree line, and it won't be long before we are sinking through to the ground in these areas.

Base depth in Gold Basin: 31"

Base depth at Geyser Pass Trailhead: 20"

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

It's looking pretty white up there. Particularly in sheltered areas between 10,000 and 11,000 feet where a base of 3'-4' exists. Extreme upper elevations have seen a lot of wind so a lot of rocks are still exposed.


Even sun exposed slopes are holding decent snow. Note the humps of barely covered rocks in the foreground however. Still good to be cautious.


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

Though the chances of triggering a persistent slab are growing increasingly unlikely, there may still be areas where the perfect combination exists of an old hard wind slab on top of buried, weak, sugary, faceted snow. The most likely areas for finding this problem are on steep, northerly aspects at and above tree line. Slopes with defined terrain features such as gullies, rock bands, or steep, convex break overs warrant extra caution.

Generally speaking, the snowpack is weakening. Sugary, faceted crystals or depth hoar are developing near the ground. Other faceted weak layers exist, and in some cases, faceting is beginning to take over the entire snowpack. This doesn't bode well for the future, and when snow returns, persistent slab problems will likely be reactivated.

weather

A fast moving storm system is moving through to the north today. By Thursday the storm track will begin to migrate south as a larger system moves into the region. Dynamics are uncertain at this time with some models showing a split trough with the upper deepening over NW Arizona. Our best chance for snow from this one will come on Friday. Ridging develops over the weekend, ahead of another system approaching early next week.

Today

Mostly sunny, with a high near 37. Breezy, with a west southwest wind 15 to 20 mph increasing to 20 to 25 mph in the afternoon. Winds could gust as high as 40 mph.

Tonight

Partly cloudy, with a low around 21. Breezy, with a west wind 15 to 25 mph.

Thursday

A 10 percent chance of snow after 2pm. Partly sunny, with a high near 34. Very windy, with a southwest wind 25 to 30 mph increasing to 35 to 40 mph in the morning. Winds could gust as high as 55 mph.

Thursday Night

Snow likely, mainly after 11pm. Cloudy, with a low around 19. Windy, with a southwest wind 30 to 35 mph, with gusts as high as 45 mph. Chance of precipitation is 70%. New snow accumulation of around an inch possible.

Friday

Snow. High near 22. Breezy, with a southwest wind 15 to 25 mph decreasing to 5 to 15 mph in the afternoon. Chance of precipitation is 80%.
general announcements

The Road to the Geyser Pass Trailhead is plowed but snowpacked. 

Grooming equipment is ready and grooming should begin this week!

Thanks for sending in your observations. You can view Moab observations here. To post an observation go here.

To receive this advisory by email go here.

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.