Advisory: Provo Area Mountains | utahavalanchecenter.org

Avalanche Advisory

Advisory: Provo Area Mountains	Issued by Drew Hardesty for Sunday - February 7, 2016 - 7:05am

bottom line

We have an overall MODERATE avalanche danger in the backcountry. Watch for new and developing wind drifts along the high elevations. Drifts may be also be loaded or crossloaded mid-slope. The likelihood of triggering a deep slab avalanche is diminishing, but the consequences remain severe. The wet avalanche activity may rise toward Considerable again today.

I'm issuing a Soapbox Warning: if you're skiing or riding the steep south-facing terrain above the road with unstable wet avalanche conditions, you may very well trigger a slide across the road or onto others below. Skinning, booting, or simply building jumps in the runout zones below at these times isn't helpful, either. #BackcountryResponsibilityObjective More to come on this...

special announcement

Tuesday February 9th - Fireside Chat at 7 p.m. at Black Diamond. UAC Forecaster Brett Kobernik will discuss current conditions and his own avalanche involvement on the Skyline from last week.

Wednesday February 10th - Avalanche Clinic for Ice Climbers at 6 p.m. at Sandy Momentum climbing gym. For more info click HERE.

current conditions

Skies are partly cloudy.

Mountain temperatures are in the mid to upper 20s.

West to northwesterly winds have awakened, now blowing 15-20mph with gusts to 35. 11,000' winds: 35-40mph with gusts to 55.

recent activity

Steep southerlies went off yesterday, at least in upper Little Cottonwood. Warming temps, direct sun, and light wind - all conspirators in the loose wet and pockets of wet slab cycle in the steepest sunny terrain. Wet slides ran not full track, but three-quarters track and left debris piles deep enough to bury you. (photo: D.Jackson, UDOT LCC).

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 Watch for wind slab development today, particularly along the highest ridgelines. Soft wind drifts of up to 12-18" may be particularly sensitive on the steep south to east facing terrain and may be triggered on approach or at a distance. These smooth, rounded drifts should be obvious along the lee of ridgelines and other terrain features. Shooting cracks and collapsing are immediate signs of instability. Click on the 'i' near the info-graphic for more info on Wind Slabs.

type

aspect/elevation

characteristics

LIKELIHOOD

LIKELY

UNLIKELY

SIZE

LARGE

SMALL

TREND

INCREASING DANGER

SAME

DECREASING DANGER

over the next 24 hours

description

Watch for wind slab development today, particularly along the highest ridgelines. Soft wind drifts of up to 12-18" may be particularly sensitive on the steep south to east facing terrain and may be triggered on approach or at a distance. These smooth, rounded drifts should be obvious along the lee of ridgelines and other terrain features. Shooting cracks and collapsing are immediate signs of instability.

Click on the 'i' near the info-graphic for more info on Wind Slabs.

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 Low probability, High consequence. The last human triggered slide was in No Name on Tuesday; the fatality along the Park City ridgeline was a week ago. These slides have generally been 2-4' deep and particularly tricky as there have often been other tracks on the slope or similar, adjacent paths skiied or ridden without retribution. They're also particularly tricky because by now they show little signs of instability - no cracking, collapsing; they're not hair trigger. You could dig a pit in one area, find stable snow and then commit to adjacent terrain that had previously avalanched and has a completely different depth and structure. Pull out your new avalanche probe (or Avatech SP2), throw away the nylon bag, and probe around snowpack depths. In general, the stable, intact depths are roughly 150-200cm or more; the repeater (conditionally unstable) avalanche snowpacks sit at 70-120cm (with fairly obvious weak snow at the base).* These are more prominent on northwest to north to easterly facing slopes above 9000' and tend to become more stressed with significant weather events. Trigger points often include thin, rocky areas. *The fine print - Side effects of putting oneself into avalanche terrain to determine structure/stability (repeaters are in avalanche terrain after all), include collapsing the slope and being caught and carried. More than one avalanche professional, aspirant, or keener has had their suspicions confirmed in this way. Other side effects do not include rashes, swelling, or baldness, though may include nausea, vertigo, broken bones, or burial. Click on the 'i' near the info-graphic for more info on Deep Slabs.

type

aspect/elevation

characteristics

LIKELIHOOD

LIKELY

UNLIKELY

SIZE

LARGE

SMALL

TREND

INCREASING DANGER

SAME

DECREASING DANGER

over the next 24 hours

description

Low probability, High consequence. The last human triggered slide was in No Name on Tuesday; the fatality along the Park City ridgeline was a week ago. These slides have generally been 2-4' deep and particularly tricky as there have often been other tracks on the slope or similar, adjacent paths skiied or ridden without retribution. They're also particularly tricky because by now they show little signs of instability - no cracking, collapsing; they're not hair trigger. You could dig a pit in one area, find stable snow and then commit to adjacent terrain that had previously avalanched and has a completely different depth and structure. Pull out your new avalanche probe (or Avatech SP2), throw away the nylon bag, and probe around snowpack depths. In general, the stable, intact depths are roughly 150-200cm or more; the repeater (conditionally unstable) avalanche snowpacks sit at 70-120cm (with fairly obvious weak snow at the base).*

These are more prominent on northwest to north to easterly facing slopes above 9000' and tend to become more stressed with significant weather events. Trigger points often include thin, rocky areas.

*The fine print - Side effects of putting oneself into avalanche terrain to determine structure/stability (repeaters are in avalanche terrain after all), include collapsing the slope and being caught and carried. More than one avalanche professional, aspirant, or keener has had their suspicions confirmed in this way. Other side effects do not include rashes, swelling, or baldness, though may include nausea, vertigo, broken bones, or burial.

Click on the 'i' near the info-graphic for more info on Deep Slabs.

Avalanche Problem 3

type	aspect/elevation	characteristics
		LIKELIHOOD LIKELY UNLIKELY SIZE LARGE SMALL TREND INCREASING DANGER SAME DECREASING DANGER over the next 12 hours
description Yesterday's wet avalanche forecast was a crapshoot. Blow the weather forecast, blow the wet avalanche forecast. For today, expect: Direct sun unimpeded by (much) cloud cover. CHECK. (Unless greenhousing noted - you'll feel damp, humid, muggy - even northerlies affected.) Rapidly warming temps. CHECK. Temps today should reach 30°F at 10,000'. Wind - can help to cool the snowpack. CHECK. Truth-be-told, the *now-cast* is pretty useful. Warning signs - The crust has broken down and the snow is wet and unsupportable. Rollerballs and pinwheels start to cascade down on their own, often from trees, tree bombs, rocky outcrops and the like. You are able to initiate push-a-lanches in the wet snow. It's a timing thing - too early on the east, south, and west and you'll find breakable and trapdoor crust. Too late and you're either the trigger or in the line of fire for wet avalanches.

type

aspect/elevation

characteristics

LIKELIHOOD

LIKELY

UNLIKELY

SIZE

LARGE

SMALL

TREND

INCREASING DANGER

SAME

DECREASING DANGER

over the next 12 hours

description

Yesterday's wet avalanche forecast was a crapshoot. Blow the weather forecast, blow the wet avalanche forecast. For today, expect:

Direct sun unimpeded by (much) cloud cover. CHECK. (Unless greenhousing noted - you'll feel damp, humid, muggy - even northerlies affected.)
Rapidly warming temps. CHECK. Temps today should reach 30°F at 10,000'.
Wind - can help to cool the snowpack. CHECK.

Truth-be-told, the now-cast is pretty useful. Warning signs -

The crust has broken down and the snow is wet and unsupportable.
Rollerballs and pinwheels start to cascade down on their own, often from trees, tree bombs, rocky outcrops and the like.
You are able to initiate push-a-lanches in the wet snow.

It's a timing thing - too early on the east, south, and west and you'll find breakable and trapdoor crust. Too late and you're either the trigger or in the line of fire for wet avalanches.

weather

We'll have at times clear skies and perhaps a few high level clouds moving through. Winds should remain gusty out of the northwest and north. Temperatures will reach near or just exceed 30°F at 10,000', the low-40s at 8000'. Looks like high pressure builds over the next week with significant warming expected by Monday into Tuesday. Tuesday's 10,000' temps soar to 40°F. In the meantime, the low density powder on the snow surface may start to facet and become weak over the next several days. The forecasters at Hatcher Pass call it "square powder". Image: Jed Workman from HPAC.

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)

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

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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.

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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 exist.

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