Forecast for the Salt Lake Area Mountains

Evelyn Lees
Issued by Evelyn Lees for
Thursday, March 7, 2019
The avalanche danger is CONSIDERABLE on all aspects at the upper elevations and mid elevation slopes facing northwest through easterly with wind drifts - triggering a 2 foot deep wind drift is likely, and natural avalanches are possible. Even in wind sheltered terrain, new snow slides a foot deep can be triggered. Careful snowpack evaluation, cautious route finding and conservative decision making are essential for backcountry travel today.

A MODERATE avalanche danger exists on other mid elevation slopes for triggering a new snow slide or wind drift, and there is a MODERATE danger on low elevation slopes for triggering a wet, loose sluff.
Low
Moderate
Considerable
High
Extreme
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Weather and Snow
Someone gave the snow globe a shake last night, and another 4 to 6” of dense snow fell at the upper elevations of the Cottonwoods and on the Park City side. This brings storm totals close to a foot in the upper Cottonwoods, with light snow continuing this morning. The storm snow is dense, averaging about 12%, containing 1 to 1 1/2 inches of water. The rain/snow line fluctuated between 7,500 and 8,000’ yesterday, but has dropped to around 6,500' this morning. Temperatures are in the mid to upper 20s.
Today: continued snow, tapering off this afternoon. An additional 3 to 7” is possible. Winds will remain from the southwest, and should decrease, averaging 10 to 20 mph, with gusts in the 30s. Speeds along the exposed higher ridge lines favored by southwest flow could still average 30 mph, with gusts in the 40s at times. Temperatures will warm into the low 30s at 8,000', and hopefully the rain/snow line will remain below 6,500’ today.
A brief break is expected this afternoon and evening before another colder system brings more snow overnight into early Friday.
Recent Avalanches
Yesterday, sensitive new snow soft slabs were easily triggered with ski cuts, averaging 6 to 10” deep in the wind drifted zones. Wet loose sluffs ran at the low to mid elevations, both natural and easily skier triggered.
Provo: natural wet loose sluffs in the Fingers on Timpanogos, 7,400’, NE, Shannon Finch photo
Numerous roofs avalanched yesterday, dumping large loads of snow into deep dangerous piles. (Matt Rollins video) Warm temperatures mean roofs will continue to shed their snow - please alert your friends and family who may not normally check avalanche forecasts. Roof avalanches can be deadly especially for children.
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Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Strong overnight winds from the southeast to southwest (averaging 30 to 35 mph, with gusts in the 40s and 50s) drifted the new snow into dense slabs. These drifts will be most widespread on northwest through easterly facing slopes at the upper elevations. The drifts could be 2 feet deep, and will be very reactive to a person or ski cuts on steep slopes, resulting in avalanches large enough to carry and bury a person.
The strong overnight winds will have also deposited snow well off the ridge lines and cross loaded drifts onto other aspects, slope break overs and along sub ridges and at the mid elevations, too. Cracking in the snow is a sign of a wind drift.

The large cornices will be more sensitive today with the added weight of the new snow on top. Stay way back from the edges, and don’t travel beneath them.
Photo by Mike and Fabian of cornice triggered wind slab, and note the large cornices along the ridge line.
Avalanche Problem #2
New Snow
Type
Location
Likelihood
Size
Description
Even out of the wind affected terrain, weak layers within the new snow and poor bonding to the old snow surfaces means you can trigger new snow slides up to a foot deep. On the shady slopes, the new dense snow fell on weaker low density snow and on the sunny slopes it landed on a hard crust. The new snow will be most sensitive during any periods of intense snowfall. Jumping on small test slopes can help give you a feel for the bonding of the new snow.
Avalanche Problem #3
Wet Snow
Type
Location
Likelihood
Size
Description
Though temperatures have cooled slightly, it will take time for the soggy snow at the low elevations to cool and strengthen. It will still be easy to get a wet loose sluff moving on steep slopes, and wet loose naturals are still possible especially during any periods of rain. Avoid steep slopes with wet soggy snow, especially gullies, creek banks or road banks where even a small slide can pile up deep debris.
Additional Information
Thinking of traveling further south to the Provo area mountains or the Mt Nebo area (recent Nebo area ob)? The snowpack is a different than in the Central Wasatch and will much more time to stabilize after this weeks storm or future storms before aiming for big objectives.
General Announcements
This information does not apply to developed ski areas or highways where avalanche control is normally done. This forecast is from the U.S.D.A. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.