US Forest Service Manti-La Sal National Forest

Introduction: Good morning, this is Max Forgensi with the USFS Manti-La Sal Avalanche Center with your avalanche and mountain weather advisory. Today is Wednesday, January 31st, 2007 at 10:00 a.m. This advisory will expire in 24 hours.

CHECK OUT OUR NEW GROOMING EQUIPMENT HERE.

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.

Please give us your observations from the field HERE. The more observations we get, the better this forecast can be.

General Conditions:

The snow started to fly last night at 8:00 pm up in the La Sals. The clouds sitting over the mountains this morning could have squeezed out 2” to 3” last night and continuing to try this morning. We still haven’t reached 100 cm (height of snow) at the Gold Basin study plot yet this year. Conditions are marginal in most areas below this snow depth although you can still find some decent turns in below tree-line areas…just be careful of ground hazards.

L.U.N.A. was up grooming on Monday, light powder skate & Nordic skiing conditions will be on tap for today. Extra blue will be the wax of choice.

The Geyser Pass Road might not be plowed this morning, and it should not give you too much trouble. 4WD is always recommended.

Mountain Weather: (At 10,500’) –

Today: Occasional snow, mainly before 11am. High near 20. West wind between 10 and 15 mph, with gusts as high as 25 mph. Chance of precipitation is 80%. Total daytime snow accumulation of 1 to 3 inches possible.
Tonight: A 50 percent chance of snow, mainly before 11pm. Partly cloudy, with a low around 15. Northwest wind between 5 and 10 mph. Little or no snow accumulation expected.
Thursday: A 30 percent chance of snow, mainly after 11am. Mostly cloudy, with a high near 19. North northwest wind between 5 and 10 mph.
Thursday Night: A 30 percent chance of snow. Partly cloudy, with a low around 6. Blustery, with a southwest wind 10 to 20 mph becoming northwest.

Weather Station/ Location	Snow Depth (HS): in./cm	New Snow (HN) in./cm	7:00 a.m. Temp (F)	Current Observations: Wind, 48 hour snow
Geyser Pass Trailhead (9,600’): (snotel link)	15.1”	2”	20	Powder conditions
Geyser Pass	~	3”	N/a	~
Gold Basin and South Mountain	30”	2”-3”	n/a	Thin, below normal coverage
Pre-Laurel Peak Station (11,705’)	N/a	N/a	8.8	NW winds 10 mph gust to 21

Avalanche Conditions: (Link to the International Avalanche Danger Scale here) –

With new snow falling in the mountains today, we have to start thinking about slab formation and avalanche activity. Let’s look at the ingredients to have a slab avalanche fail…strength, structure and energy. Stability tests (strength) are showing weaknesses in the basal layers. Depth hoar crystals exist as well as near surface facets & near crust facets. If the snow grain isn’t a facet on the ground currently, it is part of a sun-crust or an old wind slab. The structure (yellow flags) of the snow pack show 5 of 6 yellow flags being present, adding up to one RED FLAG. Finally what about the energy (shear quality). The better the quality shear, the easier that energy is to propagate to create avalanches. So what does this add up to for all of you?

We have poor strength, a bad snow pack structure and waiting for some new stored energy. Expect this new snow to bond poorly with the now buried near surface facets, creating a good sliding interface. When strong winds start to surface in the La Sals, expect wind slabs to form on leeward sides of slopes and ridges (read: stored potential energy).

The Bottom Line for today will be an Avalanche Danger of MODERATE with pockets of CONSIDERABLE on N-NE-E-SE aspects on steep slopes greater than 35 degrees.