Provo Avalanche Advisory

Forecaster: Drew Hardesty

BOTTOM LINE

Danger by aspect and elevation on slopes approaching 35° or steeper.
(click HERE for tomorrow's danger rating)


Danger Rose Tutorial

Pockets of CONSIDERABLE danger exist for old and newly developing wind slabs in the steep lee terrain. The newest wind drifts will be found in the lee of the ridgelines – primarily on northwest to northeast facing slopes approaching 38 degrees and steeper. The older drifts from Friday and Saturday are found on a wider variety of aspects and elevations. These can be triggered mid-slope or on convexities lower in the drainages.

Fast and fun LOW danger can be found in the more protected mid – elevation glades on slopes less than 30 degrees in steepness. Seems like the best bet for today.


CURRENT CONDITIONS

Happy Spring. You might call that a Wind Event yesterday. Get ready for another one. The winds were enough to knock a man over – blowing 40-50 with gusts to 70 for the bulk of the day. They preceded a nice little shot of snow overnight – the Central Wasatch picked up 8-10” ,the Provo mountains pulled in 4”, the Ogden terrain 2”. Densities average 5-6%. Riding conditions will be much improved with the snow blanketing the widespread wind damage. Temps are in the low 20s and upper teens. The southwesterly winds paused overnight just to catch its breath, but are starting to ramp back up. Along the more exposed ridgelines, they’re back to 25mph with gusts to 35. Best to get out early before the snow ends up in Woodruff, Randolph, or Evanston…


RECENT ACTIVITY

We didn't hear of any activity in the Provo mtns yesterday, but I'd bet there were some natural cornice releases if not a couple shallow wind slab releases in the steepest uncompacted terrain. In the central Wasatch,

One likely shallow natural was reported near the Summit Park area above Parley’s Canyon…the wind-prodded avalanche – at 9000’ on a north facing slope – broke 10” deep and 50’ wide. To the south along the Cottonwood ridgeline above Silver Fork, an experienced party dropped a large cornice that then triggered a 1-3’ deep and 200’ wide hard slab below. Apparently it was a ghost town in the backcountry yesterday – as I’m surprised to have not heard of more activity.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Wind slabs on top of wind slabs. The still-settling wind drifts from the past 48 hours will now be hidden beneath the new low density snow or – tragically – newly building wind drifts. The newer drifts will be sensitive to provocation, the older drifts less so. The wind drifting should become more intense and widespread as the day wears on – so be alert to changing conditions. We now have soft slabs sitting on older hard slabs –

· Soft slabs you ski or ride through – you’re in the snow, rather than on top of it – as is the case for hard slabs. Soft slabs often break at your feet or machine and are reactive to cornice drops and slope cuts. Test slopes give a good sense of the stability.

· Hard slabs – as described yesterday – are a double edged sword. There’s a lot of strength to the snow – (don’t confuse strong with stable) – making them difficult to trigger. The bad news is that the same ‘strength’ allows for significant propagation potential. This allows for hard slabs to wrap around terrain features or pull back onto lower angled slopes.

Someone skiing or riding a steep north to east facing slope shouldn’t be surprised to trigger one if not both types of these avalanches.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Cornices are massive these days and are breaking off with little prodding. The winds alone are enough to tip the scales for these monsters. They may break off on approach and trigger wind slabs or potentially deep slabs below. I feel that they’re almost too large and dangerous to be dropping intentionally.

LOOSE SNOW AVALANCHES

Loose snow avalanches on slopes approaching 40 degrees and steeper are also likely in the cold smoke. They too are easily manageable through good terrain choices and good terrain management. Keep an eye on the sluffs and move diagonally across the fall-line, stopping only on ‘ribs’ of higher ground or in the runout far below. Plenty of people riding the direct fall-line have been taken out by their own sluff. Pay attention.


THREAT #3

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

The broken record -

We’d be remiss in not mentioning the outlier

Deep Slab

problem. These are found in the mid and upper elevation north to east facing slopes. The last few have been triggered from above by massive cornice fall onto unsupported slopes below, averaging 5-7’ deep and a few hundred feet wide. Strong winds are no doubt contributing to cornice fall as we speak…


MOUNTAIN WEATHER

With the next storm approaching from the west, we’ll have mostly cloudy skies and increasing winds from the south. The winds are expected to increase to 30-35mph by early afternoon, and only ramp up more overnight through tomorrow. Temps will be in the upper teens, dropping to the mid teens by the afternoon. The next storm arrives tomorrow that looks to be a decent producer for central/southern Utah and the south slope of the Western Uintas…and perhaps the Provo and Park City mountains…


GENERAL ANNOUNCEMENTS

If you trigger an avalanche in the backcountry - especially if you are adjacent to a ski area – please call the following teams to alert them to the slide and whether anyone is missing or not. Rescue teams can be exposed to significant hazard when responding to avalanches, and do not want to do so when unneeded. Thanks.

Salt Lake – Alta Central (801-742-2033)

Ogden – Snowbasin Patrol Dispatch (801-620-1017)

Provo – Sundance Patrol Dispatch (801-223-4150)

Discount Lift tickets: Ski Utah, Backcountry.com, Alta, Deer Valley, Park City, The Canyons, Wolf Mountain, Snowbasin, Beaver Mountain, Brighton, Sundance, and Solitude have donated a limited number of tickets for sale.

Wasatch Powderbird Guides flight plan.

Dawn Patrol Forecast Hotline, updated by 05:30: 888-999-4019 option 8.

Daily observations are frequently posted by 10 pm each evening.

Subscribe to the daily avalanche advisory e-mail click HERE.

UDOT canyon closures UDOT at (801) 975-4838

You have the opportunity to participate in the creation of our own community avalanche advisory by submitting avalanche and snow observations. You can also call us at 801-524-5304 or 800-662-4140, or email by clicking HERE

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The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.

We will update this forecast tomorrow morning. Thanks for calling.


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.


This advisory provided by the USDA Forest Service, in partnership with:

The Friends of the Utah Avalanche Center, Utah Division of State Parks and Recreation, Utah Division of Emergency Management, Salt Lake County, Salt Lake Unified Fire Authority and the friends of the La Sal Avalanche Center. See our Sponsors Page for a complete list.