Wasatch Cache National Forest

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Avalanche advisory

Sunday, November 10, 2002


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Good morning, this is Bruce Tremper with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Sunday, November 10, 2002. 


We won’t have all our phone lines hooked up until next week, so you may find it easier to access this advisory on the internet.


Current Conditions:

Well, winter has finally arrived in the mountains.  About a foot of fairly dense graupel snow fell Friday and Saturday at upper elevations in the Cottonwood Canyons and about midway through the storm, rain fell up to about 9,000’.  Then at 4:00 am this morning, act II of the storm arrived with colder air on a northwest flow.  I expect that this will lay down another foot or so of snow, but this snow should be much more user-friendly than the snow from the last couple days.  Yesterday, despite being on wide skis, I found trail breaking difficult with a stiff slab sitting on top of another foot of weak, sugary depth hoar, but skiing and boarding conditions aren’t too bad if you don’t mind the sporty rocks and stumps, now buried only a foot or two down.


Avalanche Conditions:

This is the classic setup for avalanche incidents and fatalities that occur nearly like clockwork each fall in Utah.  First, we have a foot of weak, sugary depth hoar on the bottom, with the consistency of a pile of tortilla chips.  Then, we have a foot of dense snow on top of the depth hoar, kind of like putting a cast iron frying pan on top of the tortilla chips.  Next the wind created even denser and thicker slabs in the wind exposed areas—like adding two frying pans on top of the whole mess.  Then today, we have another foot of what I call “sucker snow” on top, meaning that the light density snow suckers you into thinking everything is hunky dory until you see the whole slope underneath you shatter like a pane of glass.   Yesterday, nearly everywhere I traveled above 9,000’ on the shady aspects, the slopes collapsed beneath me in these huge, booming whumphs and I could see cracks appearing up to 50 yards away, including above me.  Yikes!  Needless to say, with such obvious danger signs, I stayed on slopes of 25 degrees or less, in other words, slopes not steep enough to slide.  Another thing that make these conditions especially dangerous, people tend to go to the shady, northerly-facing, upper elevation slopes because they have just enough base snow to avoid hitting rocks, and the slopes that are safer from rocks are exactly the same slopes that are dangerous for avalanches.  You can’t win.


Today, if you want to come back alive, you should definitely avoid any slope above 9,000 feet, facing northwest, north and northeast, of 30 degrees or steeper because that’s where the old faceted snow existed before this storm overloaded it.  I have reports from several incidents of people who have triggered avalanches in terrain that fits this description and reports of another half-dozen natural avalanches, some of them quite large.  These reports came mostly from the Alta area.  Speaking of which, Alta will be closed for avalanche control all day.  People always forget this time of year that slopes at resorts that usually have moguls can and will produce life threatening avalanches because no one is doing any avalanche control.  Remember, cross one at a time, don’t jump in on your partner and carry the usual backcountry rescue gear like beacons, shovels and probes.


Bottom Line:

I would call it a  CONSIDERABLE danger on slopes above 9,000’ facing northwest, north and northeast approaching 35 degrees or steeper and HIGH on these same slopes with recent wind drifts.  If you want LOW danger terrain, stay on slopes of 30 degrees or less, well out from underneath steep slopes.


Mountain Weather:

Temperatures on the ridgetops have dropped into the mid teens with northwest winds 10-20 mph.  Snow should fall throughout the day with another foot accumulating today and perhaps another half foot tonight favored areas, such as the Cottonwood Canyons.  Snow showers should linger on Monday.  For the extended forecast, we expect warming back up to freezing on Tuesday and Wednesday with warmer southwest flow and more snow showers on Wednesday and Thursday.


General Information:

We have several free avalanche awareness talks coming up – the first two are Tuesday, November 12th at 7 pm at REI and Thursday, November 14th at 7pm at the Black Diamond Retail store. For a complete list of evening talks and multi-day classes, visit www.avalanche.org and click on Salt Lake and then Education. 


To report backcountry snow and avalanche conditions, especially if you observe or trigger an avalanche, call (801) 524-5304 or 1-800-662-4140.  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.



Evelyn Lees will update this advisory by 7:30 on Monday morning.


Thanks for calling!




National Weather Service - Salt Lake City - Snow.

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