Avalanche Advisory
Advisory: Salt Lake Area Mountains Issued by Mark Staples for Thursday - January 25, 2018 - 6:27am
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With strong winds blowing since yesterday afternoon at all elevations, the avalanche danger is CONSIDERABLE at the upper and mid elevations with both wind slab and persistent slab avalanches likely. A MODERATE danger exist at low elevations.




special announcement

TONIGHT, Fireside Chat at 7 p.m. at Black Diamond. Evelyn Lees discusses avalanche accidents when people were traveling Uphill and/or "Solo" over the past 8 winters.

We have discount lift tickets for Alta, Snowbird, Brighton, Solitude, Snowbasin,and Beaver Mountain. Details and order information here. All proceeds from these go towards paying for avalanche forecasting and education!

current conditions

It’s warm and windy this morning with temperatures above freezing up to 8500 feet. At higher ridgetops, temperatures are in the mid to upper 20’s F.

Winds are blowing 20-30 mph and gusting 40-50 mph from the S and SW. These strong winds are blowing in all places not just the highest peaks. In fact winds at 9000 ft ridgetops are nearly same as winds at 11,000 ft peaks.

recent activity

Yesterday on Pointy Peak in the backcountry above Canyons Village at Park City, a skier triggered a slide on a NE facing slope that broke 2 feet deep and 100 feet wide on weak faceted snow. They were carried about 300 feet vertical through trees but were not injured. This skier deployed their airbag backpack and was partially buried. This slope also avalanched on December 28.

In Cardiff Fork yesterday afternoon as winds began increasing, a group triggered 4 very small wind slabs on a cross loaded E-facing slope. These were about 8 inches deep and 10 feet wide.

Photo below shows yesterday's avalanche on Pointy Peak. (R. Cutter)

Avalanche Problem 1
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 12 hours
description

Strong S and SW winds have been blowing since yesterday. Even though many S facing slopes have developed an ice crust on them from the last two days of sunny weather, these strong winds will find snow to transport and form fresh wind slabs. These wind slabs should be easy to trigger today, but they may also make triggering deeper and large avalanches more likely. See below.

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

Yesterday’s persistent slab avalanche on Pointy Peak occurred before winds began transporting snow. With strong winds blowing since then and loading slopes with a similar aspect, similar avalanches will be likely today.

The snowpack on many slopes, especially ones with a northerly aspect, contains weak faceted snow near the ground and in the middle of the snowpack. There is a difference between weak and unstable. For a weak snowpack to become unstable, you need add a load of new snow which adds stress. When weak layers are stressed, they are easy to fracture and produce avalanches. Today’s winds are actively adding that stress which will make many slopes unstable. Snowfall later today will add even more stress.

weather

Strong SW winds and warm temperatures will continue until a cold front arrives this afternoon around 2 p.m. It will bring snowfall, decreasing winds and a sharp temperature drop. Temperatures will only rise a few degrees before the cold front arrives. There should be 3-6 inches of snow by tomorrow morning. Temperatures tonight will drop to near 10 degrees F.

general announcements

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This information does not apply to developed ski areas or highways where avalanche control is normally done. This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.