Avalanche Advisory
Advisory: Provo Area Mountains Issued by Drew Hardesty for Saturday - January 21, 2017 - 7:16am
bottom line

The avalanche danger is CONSIDERABLE on all aspects at the upper elevations. These loose snow avalanches and soft wind slabs are beyond manageable as the snow continues to pile up and be enough to trip up the overconfident backcountry skier or rider. With natural activity, others above you, and cornice fall likely, avoid being in the runout zone as snow will continue to move in steep terrain today. Debris piles will be more significant today.

Remember that with such low density snow, you don't even need to be on steep slopes to get your fill of powder. The safest and best riding will be on slopes less steep than 35° with nothing steeper above.




special announcement

If you sign up for AmazonSmile and designate the Utah Avalanche Center as your favorite charity, they will donate a portion of everything you spend to the UAC. I doesn't cost you a penny and we'd really appreciate the help.

I'll be hosting the Fireside Chat at the Black Diamond store in Salt Lake this Thursday at 7pm. Topic: Expert Intuition in High Risk - Low Frequency Events. Best if you have a decent grasp of the different avalanche problems, but all are welcome to this informal, low key, picnic - style gathering.

current conditions

The weather gods indeed look fondly upon the Wasatch Range. Overnight accumulations are 8" overnight with 13" total since Thursday. Southeast winds are generally light, but many areas of Provo are protected by the southeast winds. More exposed ridgelines will have speeds of 15-20mph Temperatures are in the mid 20s. Look out your window: it's still snowing.

Week in Review by Greg Gagne

Not much to report. A dominant ridge of high pressure with clear skies and cold nights through late this past week and into Wednesday led to a weakening of the snow surface on many aspects, with several observations noting surface hoar crystals as well as near-surface facets. Winds began to increase on Wednesday night and into Thursday morning, before diminishing midday on Thursday. A weak storm system deposited 3-5" in the Salt Lake mountains on Thursday.

On Wednesday, pro observer Mark White provided - as usual - an excellent observation of the snow surface prior to Thursday's small storm. Note how he highlights a thin temperature crust on west aspects that cap weaker faceted snow underneath. Observations from Thursday in the Salt Lake mountains indicated winds and warm temperatures likely destroyed the surface hoar layer ahead of the snowfall, but the layer of near-surface facets has been preserved on many shady aspects at the mid and upper elevations underneath Thursday's storm snow.
recent activity

No activity noted from the Provo mountains yesterday. In the Cottonwoods: Since 4AM this morning, natural avalanches of loose sluffs have occurred...and continue to run in the steepest terrain.
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 primary avalanche concern for today is sluffing in the very low density snow. All aspects and elevations are suspect. Old retired UDOT forecaster Dave Medara would sometimes describe these point releases as going into "hovercraft mode" and this morning's sluffs may reach that criteria. These loose low density snow avalanches start at a point, fan out, and today will pile up deeply beneath steep, sustained terrain. Consider the terrain: they'll pile up even more deeply in abrupt terrain transitions or in steep gullies or creekbeds.

HOT TIP! These sluffs may run naturally with additional snow/wind today - Remember that the most conservative terrain choices avoid being in or beneath steep slopes. At least a couple folks yesterday had to skitter out of the way of natural sluffs cascading down from above.

HOT TIP #2 With snow this light, you won't need to be on very steep slopes to enjoy the powder - in fact on the steeper (more dangerous) slopes, you might be scraping down onto the old wind or sun crusts below the fluff.

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
  • SUCKER SNOW WIND SLABS: Gusty south to southeast winds blew 30-35mph along the high peaks yesterday afternoon but these will be covered up by the additional overnight snow. The old boss called it "sucker snow" - where the still-sensitive wind drifts remained hidden beneath the alluring powder snow. There'll still be a few wind slab booby-traps in the steep east to north to west facing terrain today.
  • NEW AND DEVELOPING WIND SLABS: snow this low density needs just a whisper of wind to be eroded and then deposited onto the lee. Wind slabs may be more prevalent along the southern end of the Park City ridgeline and in other areas more exposed to the southeast winds.
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

Weak surface snow (facets and patches of surface hoar), buried by myriad sun, wind, and temperature crusts lay dormant. I don't anticipate these weaknesses to be a primary player today, but if activated with enough weight (perhaps more likely with tomorrow's additional strong winds), they'll result in larger, more unmanageable avalanches. Collapsing is a sign of instability.

weather

Expect another 4-8" today with generally light south-veering-to-west-to-northwest winds. They may be gusty at times along the ten and eleven thousand foot peaks. Temps will be in the teens. Another more energetic storm accompanied by strong southwest winds arrives tomorrow.

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.

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

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Ski Utah mobile snow updates

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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.