Avalanche Advisory
Advisory: Provo Area Mountains Issued by Evelyn Lees for Thursday - March 15, 2018 - 7:10am
bottom line

The avalanche danger is CONSIDERABLE – Dangerous avalanche conditions exist. Backcountry travel requires careful snowpack evaluation, cautious route finding and conservative decision-making. These are today's avalanche problems:

Wet loose and wet slab avalanches: can be triggered on mid and low elevation slopes of all aspects. Cornices, Glide Avalanches and Roof-avalanches are other wet snow problems today.

Deep Slab avalanches: Large avalanches 2 to 5 feet deep can be triggered in isolated areas - on steep slopes facing northwest through southeasterly at the mid and upper elevations.

Storm Snow: new snow avalanches can be triggered at the upper elevations on all aspects, especially on wind drifted slopes, and once moving trigger a deeper slide.

Better and safer conditions can be found low angle terrain at the upper elevations, with nothing steep above you.




special announcement

How does an avalanche accident happen? What is it like to be caught? What can we learn? Read a first-hand account of the avalanche accident in the Meadow Chutes that happened on January 26th. The full accident report can be found here.

A write-up of an avalanche involvement on Monday in the Little Pine couloir above LCC can be found here.


Join Mark Staples and Drew Hardesty on Monday, March 19 at 7PM for an interactive discussion of the current Wasatch snowpack conditions, a recap of some of the season's accidents, how to stay on the right side of the fracture line in our unusually weak snowpack, and their predictions for the rest of the season. The discussion will occur at RockSteady Bodyworks - 4689 Holladay Blvd Suite E in Holladay.


We couldn't get out on the snow without the great support from Polaris, Ski Doo, and Arctic Cat as well as KTM and Timbersled. Our local dealers make it happen. Tri-City Performance, Weller Recreation, Northstar's Ultimate Outdoors, Big Pine and Morgan Valley Polaris. We use these machines to monitor the snowpack across the state of Utah. We also use these machines to teach life-saving classes.

current conditions

Skies are mostly cloudy and light snow continues in the mountains. Temperatures dropped into the 20s to low 30s at the mid and low elevations in the Provo area mountains. Winds remain from the southwest, with most stations averaging 5 to 15 mph. The highest peaks to the north are averaging 20 mph with gusts in the 30s.

Yesterday, the rain/snow line started at 9,000’, then dropped to and held at 8,000’, before lowering to the valley floors overnight. Storm totals include 4 to 7” of snow in the mid elevations of the Provo area mountains, with an inch at the low elevations, containing a hefty 1' or slightly more of water. The new snow is right side up, with densities decreasing though the storm.

recent activity

Natural wet loose sluffs occurred yesterday, including on northerly facing slopes and at low to mid elevations.

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 rain soaked snow will be slow to cool at the mid and low elevations today, as it is insulated beneath a blanket of new snow. Wet loose sluffs can be triggered on steep slopes of all aspects, including northerly, and once moving may entrain snow or gouge down. Wet slabs avalanches are possible. A slide triggered in the new snow could step down into the old wet snow. The wet snow characteristics will change with elevation over surprisingly short distances. Avoid terrain traps such as gullies, creek beds and travel below steep road banks, where even a small slide can pile snow up deeply.


Cornices are increasingly sensitive and often break back further than expected. Give them a wide berth and avoid travel below them. They may also - if large enough - be enough of a trigger to pry out deeper avalanches below.

Roof-avalanches: Buildings are starting to shed their winter snow, so look up and avoid travel below steep roofs.

Glide avalanches often first occur in Stairs Gulch, Broads Fork, and Mill B South of Big Cottonwood Canyon.

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

With a new load of snow, the weak facet layers in the snowpack will be more sensitive today. These layers were responsible for the numerous deep hard slab avalanches that were triggered last week. Deep slab avalanches are typically difficult to trigger and very destructive and dangerous due to the large mass of snow involved. They are unpredictable and difficult to forecast and manage, and can be triggered by a smaller slide today.

Especially avoid steep, complex terrain with sharp break overs, rocks or cliffs and shallow snow pack areas.

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

The storm snow is right side up – dense heavy snow on the bottom with lighter snow on top – and reports are that it is well bonded to the old snow on some slopes. But the snow will be more sensitive on wind drifted slopes and upper elevation northerly slopes, the most likely places for a person to trigger a new snow slide. Snow conditions will change rapidly with elevation – so reevaluate often. If snowfall and winds increase this afternoon, the danger will become more widespread.

weather

A bit of a lull this morning, with increasing snow and wind this afternoon. An additional 1 to 3” of heavy wet snow is expected, with rain possible at the lower elevations. 9,000’ temperatures warming into the low 30s. Low elevations could warm to near 40. Winds will remain from the southwest, and increase to 15 mph averages, with gusts to 30. High peaks will average 30 mph, with gusts in the 40s. A break in the snowfall is expected tonight and Friday, with more snow and colder temperatures in the forecast for the weekend.

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.