Provo Avalanche Advisory

Forecaster: Bruce Tremper

BOTTOM LINE

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


Danger Rose Tutorial

There remains a CONSIDERABLE (Serious) avalanche danger on any slope above 8,500 feet that faces northwest, north, northeast, east and southeast, approaching 35 degrees, that has not yet slid during the previous week. You can trigger avalanches from shallower areas and they will propagate into deeper, stronger snow. Any triggered avalanches will be very large and unsurvivable. There is a MODERATE danger on slopes that have already slid and on south facing slopes. There is also a MODERATE danger on any slope approaching 35 degrees or steeper with recent deposits of wind drifted snow, which you will find mostly along the upper elevation ridges.


CURRENT CONDITIONS

It's the 3 W's this morning—wet, warm and windy. Temperatures remain very warm in the upper 20's in most locations, cloudy skies and the winds have been blowing hard from the west yesterday and overnight—25, gusting to 45 on most of the ridges and 38, gusting to 55 on the exposed peaks. Backcountry snow conditions are a mess of various wind and sun crusts with wind-packed snow near the ridges. But, you can still find some fast, soft, settled snow on the north facing slopes at upper elevations, out of the wind.


RECENT ACTIVITY

For the third day in a row, we had no reported human triggered avalanches from the backcountry, and we are psyched. Control work at the resorts continue to pull out a few, stubborn slabs. Most of the usual suspects in the backcountry have already slid and we're very psyched about that too. Photos of activity from the Provo area mountains.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

The most serious problem today remains our old nemesis, the fragile layer of faceted snow and rain crust buried about 4 feet deep. All of my snowpits the past couple days as well as observations from many other people indicate that the snowpack is strengthening and bridging. For the first time in a couple weeks, I can actually isolate a column of snow and I have to thump on it a little to get it going. But—and this is the important part—it's still capable of propagating a fracture. I call these kinds of conditions the “nuclear option” meaning that it may be difficult to trigger, but if you do, that's it. Game over. Avalanches will be 4 feet deep and almost impossible to survive. You will trigger these monsters from thin spots, on the mid or lower slopes and they will propagate into thicker and stronger snow. Although most slopes have already slid, some still hang in the balance, and these are the ones I'm talking about. We always struggle which danger rating to call these beasts. Danger ratings come from a combination between avalanche size and the likelihood of triggering. I'm calling it Considerable today—a term we all detest but we are stuck with it from an international committee. I prefer the word “Serious” and I'm actively lobbying to get it changed. According to our new, draft definitions it means “Dangerous conditions. Use conservative decision making, careful route finding and good travel habits. Training and experience are essential.” The slopes that have already slid are much safer but don't let your guard down. Some of them may have loaded up with more snow on top of the slick rain crust and they may be ready to repeat. I got back too late yesterday to post photosvideos and profiles but I will post them later today.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Our second problem today is less serious, namely, wind slabs where the strong west and southwest wind has deposited snow onto lee terrain. As always, avoid any slope approaching 35 degrees or steeper with recent wind deposits. These will look smooth and rounded. Most will be very hard but some will be soft. You will find them mostly along the upper elevation ridges on slopes that face east through north.


MOUNTAIN WEATHER

Winds should continue to blow hard from the south and southwest 30, gusting to 50. Temperatures will rise into the lower 30's along the ridges. Skies will be mostly cloudy and we will have light snow showers this afternoon before a strong cold front arrives around dinnertime. We should have heavy snow tonight with 8-12 inches on the ground by Saturday morning, then continued lighter snow showers through Saturday. When I say cold front, I mean very cold front. Ridge top temperatures will plunge to 8 below zero on Saturday night. The extended forecast calls for a little more snow on Monday and a stronger storm for the next weekend.


GENERAL ANNOUNCEMENTS

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

For the text-only advisory, click here.

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).

The UAC depends on contributions from users like you to support our work.  To find out more about how you can support our efforts to continue providing the avalanche forecasting and education that you expect please visit our Friends page.

If you’re getting out and see anything we should know about please let us know.  You can leave a message at (801) 524-5304 or 1-800-662-4140, or email us at uac@utahavalanchecenter.org. (Fax 801-524-6301).

This advisory does not apply to ski areas or highways where avalanche control is normally done. 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.