Wasatch Cache National Forest
In partnership with: Utah Division of State Parks and Recreation, The Friends of the Utah Avalanche Center, Utah Department of Emergency Services and Homeland Security and Salt Lake County.

“keeping you on top”

AVALANCHE ADVISORY

Thursday, January 11, 2007 7:30 am
Good morning, this is Bruce Tremper with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Thursday, January 11, 2007 and it’s 7:30 in the morning.

OGDEN: There will be a free avalanche talk at the Huntsville Library where Brett Kobernik be speaking along with some snow safety personnel from Snowbasin. It will be Thursday evening at 7pm. The public is welcome.

HEBER: There will be a free avalanche awareness talk for snowmobilers tonight at 7:00 pm at Nelson’s Fast Track, which is 1740 S. Highway 40.

Current Conditions:

I have to admit I’m getting a little weary of routine. I believe this is the fourth storm in a row that has come on a Thursday—my forecast day. And the storms are all eerily similar, splitting closed lows in which the center of the closed low comes right over the top of us, which are nearly impossible to forecast for snow amounts. What did I do to deserve this?

If you can’t remember my well-worn spiel from last week and the week before, etc. etc. the old snow surfaces are in bad need of some freshening up with heavily wind blasted snow at and above tree line, sun crusts on the sun exposed slopes and a few scraps of soft, settled, creamy snow in the wind and sun sheltered slopes that are mostly tracked-up.

Last night and this morning, the ridge top winds have been blowing hard from the southwest, steady 30, gusting to 50 and 40, gusting to 60 on the most exposed peaks. Ridge top temperatures have dropped into the 20’s on their way to near zero by tonight.

Snowpack and Avalanche Conditions:

Once again, I don’t think the wind or new snow today will change the avalanche conditions too much. As for the wind, there’s nothing left to blow around after the huge winds from last weekend. Second, I’m only expecting 6-10 inches of new snow and the winds should drop dramatically by mid day and much of the snow should come down without much wind. We are at that time of year when the thicker snowpack areas have a fairly solid underlying snow because the snow is thick enough to allow the faceted layers in the lower half of the snowpack to gain strength. However, the thinner snowpack areas are still composed of weak, faceted snow from top to bottom and it won’t take too much additional weight to overload the house of cards. Today you should carefully watch both sides of the teeter-totter, namely, the strength of the buried weak layers and the amount of weight piled on top of them. In the thinner snowpack areas, say less than 2 feet deep, it may require only about an inch of water weight to activate the faceted snow (a foot of new snow). In deeper snowpack areas, say more than 3-4 feet deep, it will take probably a couple inches of water weight.

Also, you will need to watch for the usual problems with the new snow, such as density inversions within the new snow and wind drifting. Be sure to jump on test slopes, do slope cuts and regularly test the new snow by digging down with your hand and pulling on small blocks.

FYI, here are some photos of avalanches from last Sunday on Box Elder Peak Photo1, Photo2, and Cascade Ridge area, Photo1.

Bottom Line for the Salt Lake, Park City, Ogden and Provo area mountains:

Today the avalanche danger will rise from LOW in the morning to MODERATE in the afternoon as new snow and wind-blown snow accumulate. If more than a foot of new or wind-blown snow accumulate the danger will be CONSIDERABLE, especially in places where the old snow is less than about 2.5 feet deep.

Mountain Weather:

Yet again (yawn) the energy of the storm is splitting and going mostly south of us into southern Utah and Arizona. We will get some snow today as the cold front passes but by this evening, the ridge top winds will die down to near zero and turn northerly, which will limit the snow tonight and on Friday. I’m optimistically expecting 6-10 inches of new snow out of this storm by Friday. The cold air boundary will linger over central Utah for most of today and Friday, so temperatures as well as snow amounts will vary dramatically depending on how far north or south you travel. But speaking of temperatures, it will be cold enough that even Craig Gordon might have to wear a hat. Temperatures will be near zero through much of the 3-day weekend and it will finally start to warm up on about Tuesday.

Announcements:

Yesterday, the Wasatch Powderbird Guides took a couple quick runs in Cascade Ridge but were shut down by wind. They will most likely not be able to get out today, but if they do they will be in Mineral, Cardiff, Days, Silver, Grizzly and White Pine, American Fork and Cascade.

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Our new, state wide tollfree hotline is 1-888-999-4019.
(For early morning detailed avalanche activity report hit option 8)

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We appreciate any snowpack and avalanche observations you have, so please leave us a message at (801) 524-5304 or 1-800-662-4140, or email us at [email protected]. (Fax 801-524-6301)

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.

Brett Kobernik will update this advisory by 7:30 on Friday morning, and thanks for calling.