Manti-La Sal Avalanche Center

US Forest Service Manti-La Sal National Forest               

Introduction:  Good morning!  This is Evan Stevens with the USFS Manti-La Sal Avalanche Center.  This is your avalanche and mountain weather advisory.  Today is Tuesday, February 22nd, 2005 at 7:30 am.  This bulletin is sponsored in part by Western Spirit, offering cycling adventures in Moab and beyond, proud sponsors of the Friends of the Manti-La Sal Avalanche Center.  This advisory will expire in 24 hours.

 

To see past advisories check out the ARCHIVE.  To see current conditions go to our WEATHER PAGE.  To see photos go to the AVIPHOTOS page.

 

General Conditions:

Not much change.  We did get a little new snow last night.  You can still expect great powder in the sheltered areas and wind affected snow everywhere else.  The more open North through East aspects still have sizeable wind slabs sitting on them, as do some other unexpected cross loaded slopes. 

The road to the Geyser Pass Trailhead was plowed Sunday; a big thanks to the Grand County Road Crew.  4WD or chains (or both) will be useful for driving up there. 

 

Current Conditions: (click location for latest data)

Geyser Pass Trailhead (9,600’):  57” at the stake, it is 25 degrees at the TH at 6:00 am. 

Pre-Laurel Peak (11,700’): AARRGGHH!  Back to the drawing board on this one, hopefully by Monday evening we’ll have read-outs.   

Gold Basin and South Mountain:  79” of settled snow on the ground. 

 

Mountain Weather: (At 10,500’)

A weak disturbance that came through last night will be on its way out this morning and could leave us with a little more snow.  The low pressure off California will slowly make its way towards us and may bring light snow our way by mid-week.

Tuesday. Snow showers are likely in the morning and will be scattered in the afternoon with 2-4” accumulating.  Highs in the 30s.  Southwest winds 10-15 mph.
Tuesday night. Mostly cloudy with a 40% chance of snow.  Lows in the 20s.  Southwest winds 10 to 15 mph becoming light in the evening.
Wednesday. Cloudy with a 50% chance for more snow.  Highs in the 30s.  East winds 10 to 15 mph shifting to the north in the afternoon.
 

Avalanche Conditions:

Unfortunately not much has changed out there.  The wind is still blowing snow, and we still have the ingredients for some serious avalanches: strong, stiff, reactive wind slabs sitting on older persistent weak layers.  All we need to add to the mix is a trigger.  When the weather cleared yesterday, I could see some huge cornices perched ominously above many slopes in Gold Basin.  Smaller cornices on my test slopes have been breaking easily and triggering slides in the slopes that they land on.  Of course the trigger could be much smaller, like your weight above a trigger point in the slope: a shallow rock outcrop, a tree, a convex rollover, or maybe one of those smaller wind slabs in an unexpected place.  On the more heavily loaded slopes your added weight might be enough to make the slope fail if you are anywhere on the slope.  The wind slabs’ stiffness allow forces to propagate farther, so you could even trigger a slope while standing or skiing on a much less steep part of it.  The trigger could also be as simple as more snow from wind loading or the accumulation we got last night and are supposed to get today.  Some things we have in our favor are the temperatures have been relatively mild and our snow pack is pretty deep.  Some of those old weak layers are SLOWLY starting to build more cohesive bonds.  We just have to be patient.

For today be on your toes, use the terrain to mitigate the avalanche hazard by traveling on ridgelines, in sheltered lower angle areas, and avoiding the steeper wind loaded slopes (mainly the N-E aspects, but with lots of smaller wind slabs in unexpected places).  If you do venture into avalanche terrain, make sure you use safe travel techniques like only putting one person in harms way at a time, moving quickly and efficiently through the danger, and having an escape plan.  Find some small, steep, and, most of all, safe test slopes, and hammer on them: any cracks or slides?  Step off the skin track, and feel the snow pack beneath you: any whumphs or collapsing? Do you see any recent avalanches?  Where are those wind-loaded areas: look for ripples, sastrugi, cornices, drifts, or riming on the trees?  Watch out for run out zones, and make sure that you are well away from where a slide would end.

 

The Bottom Line for today:  An overall avalanche danger of CONSIDERABLE on slopes steeper than 30 degrees.  The snow pack is especially sensitive in the steeper more heavily wind loaded areas like those North through East aspects, but don’t forget about the other unexpected pockets of wind slab well into the trees, farther down slope from the ridgelines, hiding behind features on SW aspects, and on cross-loaded slopes.  Have fun and be safe.

 

 

Nordic and Skate Skiing:

There is a classic track set into Gold Basin and up to Geyser Pass.