Avalanche Advisory
Advisory: Salt Lake Area Mountains Issued by Mark Staples for Tuesday - December 22, 2015 - 6:16am
bottom line

Today the avalanche danger is HIGH. Travel in or even near avalanche terrain is NOT recommended. Avalanches may break within the new snow or near the ground. Do not go into the backcountry if you do not know how to identify and avoid avalanche terrain.
avalanche warning

THE FOREST SERVICE UTAH AVALANCHE CENTER IN SALT LAKE CITY HAS ISSUED A BACKCOUNTRY AVALANCHE WARNING.

* TIMING…IN EFFECT FROM 3:30 PM MST MONDAY TO 6 AM MST WEDNESDAY

* AFFECTED AREA…ALL THE MOUNTAINS OF NORTHERN UTAH AND SOUTHEASTERN IDAHO, TO INCLUDE THE WASATCH RANGE, THE BEAR RIVER RANGE, THE WESTERN UINTAS AND THE MANTI-SKYLINE PLATEAU. OTHER MOUNTAIN RANGES NOT LISTED WILL LIKELY BE AFFECTED AS WELL.

* AVALANCHE DANGER…THE AVALANCHE DANGER FOR THE WARNING AREA IS HIGH

* IMPACTS…HEAVY SNOW COMBINED WITH WIND IS CREATING WIDESPREAD AREAS OF UNSTABLE SNOW. BOTH HUMAN TRIGGERED AND NATURAL AVALANCHES ARE LIKELY AND WILL OCCUR IN MANY AREAS. STAY OFF OF AND OUT FROM UNDER SLOPES STEEPER THAN 30 DEGREES.

THIS WARNING DOES NOT APPLY TO SKI AREAS WHERE AVALANCHE HAZARD REDUCTION MEASURES ARE PERFORMED.

See this VIDEO about the Avalanche Warning and High Avalanche Danger.
special announcement

The Vail Resorts EpicPromise program has donated an Epic Pass to the Utah Avalanche Center to sell as a fundraiser. The price is $809. For more details, email us or see the description on Facebook

Interested in going to one of our world class ski resorts? Buy discount lift tickets to Utah resorts and benefit the Utah Avalanche Center! Details here
current conditions

Snowfall began yesterday but increased significantly this morning in the Cottonwood Canyons. As of 4 a.m. upper Big Cottonwood Canyon received 17-19 inches of snow (1.4-1.7 inches of water) and upper Little Cottonwood Canyon received 9 inches of snow (0.7 inches of water) since yesterday morning. It is still snowing. Winds yesterday were cranking from the SW at 40-50 mph, but calmed some this morning as they shifted to the W and WNW blowing 15 mph gusting to 30 mph. The rain/snow line seems to be around 6000 ft. Temperatures above 9000 feet are in the low 20s F.
recent activity

Most of the reported avalanche activity yesterday occurred within the storm snow. Some of these slides occurred midday before the heaviest snowfall. There were several naturals observed in Big Cottonwood Canyon near the Honeycomb Cliffs that started in the storm snow then stepped down and broke in facets at the ground. Skiers near the Park City Ridgeline reported triggering a NE facing slope from 1/4 mile away.
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

There are several density changes in the new snow on which storm slab avalanches will break. Avalanches will also break on top of a crust that formed on Friday and is now buried 1-2 feet deep. Storm slab avalanches will be most sensitive on any wind loaded slope, but I don't think you need any wind to get an avalanche today. Additionally, avalanches initiating in the new snow can step down and cause large, persistent slab avalanches breaking at the ground (see Avalanche Problem 2 below).

Skiers yesterday observed cracking in the new snow in the West Fork of Silver Fork (a sure sign of unstable conditions) that was fracturing on top of Friday's crust (J. Hutchinson photo).

A snowboarder triggered this avalanche in upper Big Cottonwood. You can see him making a turn buried in powder a second before the slide released. It broke 2 ft deep and 30 ft wide on a slope with 20 ft of vertical but produced a debris pile 5-6 ft deep.
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

Prior to this storm, persistent slab avalanches have been triggered remotely (mostly along the Park City ridgeline) and fractured on facets near the ground. Many of these slides have been on wind loaded slopes facing generally NE loaded by yesterday's strong SW winds. Even south aspects have weak faceted snow near the ground. The only difference is that there are several ice crusts on top of these weak facets. I don't think that persistent slab avalanches are as likely on south aspects but I wouldn't be surprised to hear of one occurring. Other observers have reported collapsing and cracking of the snowpack and propagating fractures in stability tests. These are all signs that weak facets near the ground will produce large persistent slab avalanches today.

Photo of strong SW winds loading slopes along the PC ridgeline yesterday (M. White photo).

Photo of obvious weak facets near the ground on which persistent slab avalanches will occur (UAC photo).
weather

Snowfall should continue this morning and slow down by this afternoon. Temperatures should remain in the 20s F and winds at 9000 ft should blow 15-25 mph from the WNW. This WNW flow should continue to favor Little Cottonwood Canyon which received less snow overnight than other areas. By tomorrow morning there should be another 6-10 inches of snow.
general announcements

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 by submitting snow and avalanche conditions. You can also call us at 801-524-5304, email by clicking HERE, or include #utavy in your tweet or Instagram.

To get help in an emergency (to launch a rescue) in the Wasatch, call 911.  Be prepared to give your GPS coordinates or the run name. Dispatchers have a copy of the Wasatch Backcountry Ski map.

Backcountry Emergencies. It outlines your step-by-step method in the event of a winter backcountry incident.

If you trigger an avalanche in the backcountry, but no one is hurt and you do not need assistance, please notify the nearest ski area dispatch to avoid a needless response by rescue teams. Thanks.

Salt Lake and Park City – Alta Central (801-742-2033), Canyons Resort/PCMR Dispatch (435)615-1911

Snowbasin Resort Dispatch (801-620-1017), Powder Mountain Dispatch (801-745-3772 x 123).

Sundance Dispatch (801-223-4150)

EMAIL ADVISORY  If you would like to get the daily advisory by email you will need to subscribe here.​ 

DAWN PATROL Hotline updated daily by 5-530am - 888-999-4019 option 8.

Twitter Updates for your mobile phone - DETAILS

UDOT canyon closures:  LINK TO UDOT, or on Twitter, follow @UDOTavy, @CanyonAlerts or @AltaCentral

Utah Avalanche Center mobile app - Get your advisory on your iPhone along with great navigation and rescue tools.

Powderbird Helicopter Skiing - Blog/itinerary for the day

Lost or Found something in the backcountry? - http://nolofo.com/

Ski Utah mobile snow updates

To those skinning uphill at resorts:  it is your responsibility to know the resort policy on uphill travel.  You can see the uphill travel policy for each resort here. IMPORTANT: Before skinning or hiking at a resort under new snow conditions, check in with Ski Patrol.  Resorts can restrict or cut off access if incompatible with control and grooming operations.

Benefit the Utah Avalanche Center when you shop from Backcountry.com or REI:  Click this link for Backcountry.com or this link to REI, shop, and they will donate a percent of your purchase price to the UAC.  Both offer free shipping (with some conditions) so this costs you nothing!

Benefit the Utah Avalanche Center when you buy or sell on ebay - set the Utah Avalanche Center as a favorite non-profit in your ebay account here and click on ebay gives when you buy or sell.  You can choose to have your seller fees donated to the UAC, which doesn't cost you a penny.

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 exist.