Avalanche Advisory
Advisory: Moab Area Mountains Issued by Eric Trenbeath for Monday - December 16, 2013 - 7:29am
bottom line

Though the avalanche danger is currently LEVEL 2 (MODERATE) at this time, there are currently three types of avalanches to be concerned with. The first danger exists on mid to upper elevation slopes steeper than about 35 degrees that have a NW-NE aspect. The danger here continues to be buried persistent slabs that overly weak, sugary snow. The second danger is recently deposited wind slabs from the strong NNW winds we have been experiencing. This danger is most prevalent on upper elevation east and southerly aspects, but cross loading has affected other slopes, so pay attention to things like gully walls and the lee sides of terrain features. And finally, with warming temperatures, the third problem we need to be aware of is wet slide activity on sun affected slopes. Elsewhere, the avalanche danger is generally LOW.
special announcement

The following advisory describes snow and avalanche conditions based on field observations taken the weekend of December 14-15, and from weather data obtained on Monday morning, December 16. This information should be used as a baseline and winter back country users will need to take into account current weather conditions and their effects on the avalanche danger when they head into the mountains this week.

current conditions

The weekend was quite warm in the mountains, with clear skies and temperatures near 30 degrees at 10,000'. A mixed bag of surface conditions exists including a variety of sun and wind crusts. Winds picked up Saturday night, and have continued through this morning, averaging 20 mph with gusts to 40 out of the NNW. Best bet now for settled, re-crystallized, powder conditions will be on sheltered northerly aspects below tree line. There is currently 21" on the ground at Geyser Pass Trailhead, and 35" in Gold Basin.
recent activity

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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

Buried, persistent slabs remain a concern. Though the odds of triggering these slabs are growing less likely, weak faceted snow still underlies them. Overall, it's not a great recipe, and a slide triggered under these conditions wold be large and dangerous. Continue to avoid steep, northerly facing, upper elevation terrain. Be particularly leery of rocky terrain and areas beneath cliff bands. Suspect areas with a smooth, rounded appearance, and be alert to the many steep convexities in our mountain range. This type of terrain can lure you far down a slope to where if a slide is released, it will fracture well above you.
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 strong, gusty, NW winds, have blown available snow around at the upper elevations creating new wind slabs along ridge crests primarily on slopes with E-SE-SW aspects. Also be alert for cross loading on upper elevation, northerly aspects on the lee sides of terrain features. Look for characteristic, rounded pillows indicating recent deposits of wind drifted snow.
Avalanche Problem 3
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

With steadily warming temperatures this week, you will need to be alert to the dangers of wet slide activity on slopes steeper than about 30 degrees with a southerly aspect. Be alert to signs of instability such as wet, slushy snow, roller balls or "cinnamon rolls" coming down the hill, and of course, wet slide activity itself. As daytime temperatures climb, stay off of, and out from under these slopes.
weather

Sunny skies and steadily warming temperatures are in line for the next few days as we remain under a dry, northwest flow. Daytime highs will approach 30 degrees on Monday, and will climb on up to the mid to high 30's by Wednesday. Winds should taper off and continue to blow from the NW, swinging around to southerly by Tuesday. A spilt trough and strengthening SW flow will move into our area Thursday, though it appears that most of the energy is diving south, leaving us with cloudy skies, cooler temperatures, and only a chance for snow.

For the most up to date wind and temperature conditions, go to our automated weather station at 11,600' on Pre Laurel Peak click here: http://mesowest.utah.edu/cgi-bin/droman/meso_base.cgi?stn=lsl

For new snow totals in Gold Basin click here: http://mesowest.utah.edu/cgi-bin/droman/meso_base.cgi?stn=goldb
general announcements

OBSERVATIONS: If you are out and about in the mountains, I'd love to know what you are seeing. Please submit your observations here: http://utahavalanchecenter.org/bc_obs_1 

To view observations posted by others, go here: http://utahavalanchecenter.org/observations/moab

LUNA GROOMING INFORMATION: Thanks to all who came to the grooming training yesterday! Grooming has begun, and with this weather pattern, skating and cross country skiing may be the sport of choice. 

ROAD CONDITIONS: Plow crews will be initiating road closures during plowing this season due to conflicts with traffic. The plan is to call me the day before they plan to plow so I can post it in this advisory. This closure could take up to two hours so please plan accordingly. Do not expect plowing over the weekend. San Juan County does an excellent job keeping our road open but please keep in mind that their first priority after a storm is to open roads in and around populated areas.

UAC MOBILE APP: Get your advisory on your iphone here: https://itunes.apple.com/us/app/utah-avalanche-center/id605579982?mt=8