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 dot the upper elevation wind drifted landscape in the southern Wasatch. Drifts will be most pronounced in upper elevation northeast through southeast facing slopes. Isolated naturals may be possible with so much snow to blow around. Out of the wind, the danger has diminished to Moderate in the storm snow. Consider the terrain beneath you if you get knocked off your board(s) or ride.

CURRENT CONDITIONS

Words cannot describe the onslaught of snow. With another 1-4” overnight, storm totals since Monday night are 28-32” in the Logan and Ogden area mountains, 24-28” in the Cottonwoods and Provo mountains, and 16-18” in the Park City environs. 6.5 inches of “snow-water-equivalent” at the Ben Lomond snotel site is unbelievable; and human confirmation there is, as always, warranted. Winds are now from the west northwest blowing 18-25mph along the ridgelines with gusts to 35….and less than 15mph in the more sheltered terrain. Temps are in the teens. Riding conditions? Bust out the snorkels and avoid the tree-wells.

RECENT ACTIVITY

It doesn’t take a snow scientist to forecast a natural cycle when it’s snowing 3-4”/hour. There’s just not enough time for the snow to bond and gain strength, so it fails along the old snow surface or within the storm snow due to irregularities in density/crystal type/wind, etc. That being said, we experienced at least two natural cycles during the storm. Large, long running naturals ran full track on Timpanogos above Sundance, though we only heard about road activity on a closed SR-92 to Sundance and up toward Powder Mountain. Most travelled in benign terrain, though I did see one snowmobiler trigger and ride a shallow sluff down the back of Clayton Peak.

THREAT #1
WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

The snowpack is quite varied across the range. The Ogden and Logan mountains put 30” of snow over a tricky mid-pack layer of surface hoar and near surface facets. They’ll continue to deal with storm snow avalanches, wind slabs, loose sluffs, and the insidious mid-pack layering. There is some potential for large human triggered slides in this layer up to 4’ deep and a couple hundred feet wide, particularly with large triggers, such as a cornice fall or snowmobile. Avoid the steep north through east facing slopes for another few days until stability increases on both the storm layers and the mid-pack.

In the Provo mountains, 16-18” of graupel easily overloaded the initial 4” of very light density snow, producing widespread activity to include remote and sympathetic triggering at many aspects and elevations. This structure may be slower to heal and it may take a couple days for settlement to allow the snowpack to adjust.

In the Central Wasatch, stability for the storm snow and loose snow avalanches will be on the rise, though the upper elevations will have some increased danger due to newly formed wind drifts. They’ll be most pronounced just off the ridgelines on terrain facing northeast, east, and southeast. Persistent instabilities are generally localized to the shady mid and low elevations and should be a consideration with exits into steep gullies and terrain traps. The sheer amount of snowfall has pushed much of these problems into the unmanageable category, where it may be difficult to get enough initial speed to perform a ski or slope cut……and cornices are so large and menacing that you might go over with the box-car, as it breaks back farther than expected.

THREAT #2
WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Here are the key points:

1. Are you in or underneath avalanche terrain?

2. Can the slope slide?

3. What will happen if it does?

Slope angle, slope angle, slope angle. Only a few degrees of steepness make the difference. Probability will increase from 35 degrees toward 40 to 42 degrees. Those entering steep terrain will want to follow strict travel protocol, ski and ride one at a time, and get out of the way at the bottom.

THREAT #3
WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

see above

MOUNTAIN WEATHER

A moist unstable northwest flow should allow for another couple inches of snow throughout the day. Temps will be in the teens. Winds are expected to blow 20-25mph this morning and diminish over the next few hours. High pressure builds for the remainder of the week with the next storms forecast for late in the weekend.

GENERAL ANNOUNCEMENTS

Thanks to Doug Wewer for coordinating our Level 2 avalanche class at Brighton. He and his wife Katie have done a standout job for us over the years.

Our web page is now mobile-friendly for users of iPhone and iPod Touch.

Wasatch Powderbird Guides. Operations planning page is here.

Beacon training parks are up and running! There is one at Snowbasin, one on the Park City side at the top of Canyon’s gondola toward the Tombstone lift, one in Little Cottonwood near the Snowbird parking structure on the bypass road, and in Big Cottonwood a training park is at the west end of Solitude's lower parking lot.

If you want to get this avalanche advisory e-mailed to you daily click HERE.

For a text only version, the link is on the left side bar, near the top.

UDOT highway avalanche control work info can be found by calling (801) 975-4838. Our statewide toll free line is 1-888-999-4019 (early morning, option 8).

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Your snow and avalanche observations help everyone in the backcountry community. Please let us know what you're seeing by leaving a message at (801) 524-5304 or 1-800-662-4140, or email us at uac@utahavalanchecenter.org. (Fax 801-524-6301).

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.

Evelyn Lees will update this advisory by 7:30 tomorrow morning.

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.