Avalanche Advisory
Advisory: Salt Lake Area Mountains Issued by Brett Kobernik for Saturday - January 12, 2013 - 6:50am
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ODD WEATHER = ODD AVALANCHES. There is a CONSIDERABLE danger in the lower and especially mid elevations that have received more than about a foot of snow. The mid elevations are the most dangerous where more than a foot of snow landed on preserved weak snow from earlier in the month. UNFORTUNATELY THESE AREAS HOLD THE BEST RIDING CONDITIONS AND WILL DRAW YOU IN. Stay out of terrain traps in the foothills until the new snow settles for a day or so. A CONSIDERABLE danger exists in all of the terrain above Bountiful and Farmington which has received a large amount of snow.




current conditions

What the heck gives? More snow OUTSIDE of the beloved upper Cottonwoods? Are you nuts? Nope, it's the truth people. The upper Cottonwoods are only up to around a foot of snow or a bit more and the lower elevations around the foothills are over two feet. What happened? The simple answer is it got too cold to snow at the upper elevations. The best temperature range for dendridic crystal growth occurred in the lower elevations where it was a bit warmer. The addition of a favorable westerly flow absolutely clobbered Davis County and the mountains above Bountiful and Farmington with upwards of 40" of snow and 3" of water!! We have sub-zero temperatures above around 9000 feet, the coldest of the season so far. Anemometers didn't portray a very good picture of the winds from yesterday in my opinion in the higher terrain. They didn't look like much on paper but they were definitely slightly annoying once you were in the field with a decent amount of drifting occurring from a predominantly west direction but I noted lots of variation down in the terrain features. THIS ODD WEATHER EVENT DEMANDS OUR ATTENTION. ODD WEATHER=ODD AVALANCHES.

recent activity

One avalanche was reported yesterday from Depth Hoar bowl in Alexander Basin. Very fitting name however it was near surface facets that acted as the weak layer. It was a skier triggered soft slab that was 18 inches deep, fifty feet wide and ran about 500 vertical feet. As persistent weak layers (faceted weak layers) often do, it allowed the skier to get well down on the slope before releasing above him. Luckily the slab was so soft that it just washed around him. Once he was clear, his partner was able to trigger the hangfire or the piece of snow left above the original fracture line.

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

The slide in Depth Hoar bowl is the perfect example of what poses the greatest threat to people today. It had everything you need to trigger an avalanche which includes a sheltered area where the facets from the last two weeks are preserved and received enough new snow to overload them. Keep in mind that a rime crust may be capping these facets in places as well but the end result still can be the same with the old facets collapsing. You need to be in areas that have enough weight from the new snow which would be over about 10" of new snow or so. I feel this is a spotty problem perhaps making it more dangerous by allowing your confidence to build in not seeing much signs of instability until a certain slope collapses.

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 new snow itself could still pose a threat today but the peak of its instability has past. Some areas have received a large amount of new snow and we always treat those areas with caution directly after such an event. The odd thing is here is that the large snow amounts are in locations that don't usually get so much snow. This could take people off guard. Be very careful if you're screwing around in the foothills. Avoid gullies or "terrain traps". Small avalanches can pile up very deep in confined areas and be very dangerous.

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

Even though the anemometers didn't show much, the winds no doubt played a role in drifting snow around and it wasn't just limited to the highest terrain. The wind slabs themselves in the upper elevations were stubborn yesterday. The most dangerous situation will be where the winds drifted in snow deep on top of the recent weak facets which is most pronounced in the mid elevations.

weather

It's going to be very cold with some periods of snow. A few inches of accumulation is possible in the higher terrain and perhaps a little more in the foothills. Winds should be not quite as strong today as yesterday and start out more westerly veering more northerly as the day goes on. Very cold temperatures continue through Sunday and Monday as ridging sets in an things rebound a bit.

general announcements

Go to http://www.backcountry.com/utah-avalanche-center to get tickets from our partners at Park City, Beaver Mountain, Canyons, Sundance, and Wolf Mountain. All proceeds benefit the Utah Avalanche Center.

If you trigger an avalanche in the backcountry - especially if you are adjacent to a ski area – please call the following teams to alert them to the slide and whether anyone is missing or not. Rescue teams can be exposed to significant hazard when responding to avalanches, and do not want to do so when unneeded. Thanks.

Salt Lake and Park City – Alta Central (801-742-2033), Canyons Resort Dispatch (435-615-3322)

Ogden – Snowbasin Patrol Dispatch (801-620-1017)

Powder Mountain Ski Patrol Dispatch (801-745-3773 ex 123)

Provo – Sundance Patrol Dispatch (801-223-4150)

Dawn Patrol Forecast Hotline, updated by 05:30: 888-999-4019 option 8.

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Daily observations are frequently posted by 10 pm each evening.

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UDOT canyon closures UDOT at (801) 975-4838

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Remember your information can save lives. If you see anything we should know about, please participate in the creation of our own community avalanche advisory bysubmitting snow and avalanche conditions. You can also call us at 801-524-5304 or 800-662-4140, or email by clicking HERE

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For a print version of this advisory click HERE.

This advisory is produced by the U.S. Forest Service, which is solely responsible for its content. It describes only general avalanche conditions and local variations always exist. Specific terrain and route finding decisions should always be based on skills learned in a field-based avalanche class