Avalanche Advisory
Advisory: Salt Lake Area Mountains Issued by Mark Staples for Tuesday - April 25, 2017 - 6:47am
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Heavy snow started falling at 11 am yesterday and was still falling this morning. That amount of snow by itself can cause avalanches. At upper elevations, strong W and NW winds blew overnight and formed fresh wind slabs that should easily fracture this morning.

Most ski resorts are closed for the season they no longer perform avalanche mitigation, so treat them just like backcountry terrain.‚Äč Additionally, be sure to follow any restrictions closed resorts may have for uphill travel.




special announcement

We have stopped issuing regular avalanche advisories for the 2016/2017 season. For the rest of the month we will issue Friday updates for the central Wasatch Mountains and updates any time there is measurable snowfall; however, we have discontinued issuing avalanche danger ratings altogether.

Watch the video below about things to watch for this spring.


This does not mean the end of avalanches. Spring storms and warm temperatures may make avalanche danger rise. If you scroll down, we provide some general avalanche advice to follow for typical spring weather patterns and we provide a series of other links you can use for current conditions and mountain weather.

current conditions

As of 6 a.m. in Little Cottonwood Canyon at 9700 feet, 15 inches of snow fell containing 1.5 inches of water. At 7400 feet in Big Cottonwood, 4 inches of snow had accumulated. The Snowbird webcam image from 6 a.m. showed over 12 inches of snow with more falling.

Temperatures were at freezing yesterday during the start of the storm and had dropped to 23 degrees F this morning at 9700 ft. At higher elevations, temperatures started in the upper 20's F and were in the upper teens and low 20's this morning. These temperatures mean that snow started warm and dense and became lighter and drier as the storm progressed overnight.

Winds from the W and NW are a concern at the highest elevations. While they calmed a bit this morning, overnight winds were blowing:

  • At 11,000 feet -> averaging 30 mph, gusting 40-50 mph
  • At 10,500 feet -> averaging 15-20 mph, gusting 30-40 mph
  • At 9,400 feet -> averaging 10 mph, gusting 18 mph

For more information:

  • Weather stations and wind sites click HERE.
  • Weather forecast and discussion click HERE.
  • NOAA snow and avalanche page click HERE.

recent activity

East winds this weekend transported the new snow from last Thursday/Friday and formed some fresh wind slabs. At least three slides were triggered near Alta (which is closed and has backcountry conditions) on slopes above 10,000 ft on Saturday. These averaged about 12 inches deep. My partner and I triggered a wind slab on Friday that broke about a foot deep on a layer within the storm snow. By Sunday, wet loose avalanches occurred as temperatures warmed and strong sunshine made the new snow wet.

Although we will be shutting down regular operations, we will continue to post recent avalanche activity and observations, so please do continue to send them to us. You can check the latest observations here. We also follow avalanche-related activity on Instagram - be sure to tag your photos with #utavy .


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

Storm Slab Avalanches - The red flag this morning is snow falling at the rate of several inches per hour. There are likely several different layers in the new snow (and probably some graupel) that could act as a weak layer for today.

  • Step uphill of a skin track and see where or if the snow fractures. If cracks shoot forward any distance, its a sign of unstable snow.
  • Jump on small test slopes to test bonding of the new snow.

Fortunately, this storm started warm and became cooler which produced "right side up" snow. This is a good sign. However, snowfall has been intense which means it will need more time to stabilize. Additionally, watch for warming temperatures and continued snowfall today which could make the new snow become "upside down" meaning there is heavier snow on top of lighter snow.

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 15 inches of snow, more falling, and strong overnight winds from the W and NW, watch for fresh wind slabs on slopes at upper elevations. Wind slabs could easily be 2 feet deep. I would be surprised not to hear about wind slab avalanches being triggered today at the highest elevations.

Wind slabs formed overnight may be hidden by snow falling this morning, so pay attention to how the snow feels under your feet. If it feels slabby, punchy, or stiff, it is likely a sign of a fresh wind slab that could fracture and produce an avalanche.

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

Wet Snow Avalanches - These are always a possibility in the spring. Although no sunshine is forecasted today, watch for any rain falling on new snow which would cause loose, wet avalanches to occur. This should only be an issue at lower elevations.

Glide Avalanches - Although lower elevations and south aspects are beginning to melt out, there is still a deep, 10' snowpack in the upper elevations. The following aerial photo from April 5 shows glide cracks in Stairs Gulch. With a deep snowpack in the alpine regions, Spring mountaineering conditions are prime right now in the Wasatch. However, certain drainages in Big Cottonwood Canyon - including Stairs Gulch, Mill B South, and Broads Fork - are also known paths for glide avalanches, and this terrain should be avoided. (We received an excellent, personalized observation discussing glide avalanches, and you can also visit Bruce Tremper's blog on glide avalanches as well.)

weather

From the National Weather Service office in Salt Lake City:

"A low pressure system aloft will maintain periods of snow through today. High pressure will briefly follow tonight into Wednesday morning, before another series of storm systems impacts the region for the latter half of the week."

Temperatures today at 8500 feet should rise to near 30 degrees F. Snowfall will continue but taper off this afternoon producing another 3-6 inches . Winds at 11,000 feet should blow 20-30 mph from the NW and gust up to 45 mph. At ridgelines at 10,000 feet, winds should blow 10-20 mph.

general announcements

Remember your information can save lives. If you see anything we should know about, please help us out 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 request 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.

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 critical to know the resort policy on uphill travel.  You can see the uphill travel policy for each resort here

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 occur