Avalanche Advisory
Advisory: Moab Area Mountains Issued by Bruce Tremper for Friday - February 5, 2016 - 6:43am
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A CONSIDERABLE avalanche danger of human triggered avalanches remains today, meaning "Dangerous conditions. Choose conservative terrain." You'll likely find human triggered avalanche potential in two types of terrain: 1) on the buried, persistent weak layers in the preexisting snow on the shady aspects, such as northwest, north, northeast and east facing slopes. 2) on any steep slope with recent wind deposits.




special announcement

Geyser Pass road update:
The Forest Service has paid a contractor to plow the Geyser Pass road and it's now open again.

Here's a video version of this advisory I created last night. It contains video of the Horse Creek avalanche we looked at on Wednesday.

current conditions

This is Bruce Tremper, filling in for Eric Trenbeath who should be back on Monday.

Wednesday, we used snowmobiles to get up the Geyser Pass road from the junction with the plowed road. We broke trail on skis to Pre-Laurel Peak to have a look at the avalanche activity during the storm and we were not disappointed (see below).

All the new snow settled into a little over a foot deep. The storm deposited relatively dense, rimed snow and combined with the below zero temperatures, it was a bit stiff and you needed to be on steeper terrain to get going on skis.

We got a couple inches of new snow from the little disturbance yesterday. It warmed up a bit yesterday but it's cold again with temperatures just above zero and the wind is blowing out of the north on Laurel Peak 20, gusting to 40.

Winds, temperature and humidity on Pre-Laurel Peak

New snow totals, temperature and humidity in Gold Basin

Total snow depth and temperature at Geyser Pass Trailhead

recent activity

I have to admit I'm quite happy that my forecast during the storm was spot on--High danger along with an Avalanche Warning. Most of the avalanche paths on the upper elevation shady aspects avalanched during the storm. There are too many to mention, but we could see lots of activity off Tuk-No, Red Snow Cirque, Middle Cirque, Talking Mountain Cirque and Horse Canyon, to name a few.


It's hard to see the widespread avalanche activity in these photos because many of them ran in the middle of the storm and subsequent snow covered them up. But the debris piles at the bottom give them away.

I took this photo from where I'm doing a fracture line profile on the flank of the big avalanche in Horse Canyon. It was about 1-2' deep and perhaps 200 yards wide.


Although this accident happened in central Utah in Huntington Canyon, it's close enough to Moab to pay attention. Wednesday, one of our experienced forecasters for the Utah Avalanche Center triggered an avalanche at 9,000' in burned trees and was injured. HERE is a preliminary report.

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

Although most of the usual-suspect slopes avalanched during the storm, I noticed no lack of identical-looking slopes that remain hanging, perhaps waiting for a trigger. If you must ski or snowmobile steep, shady aspects, you should do it on something that has avalanched recently and don't provoke the other slopes that did not slide during the storm. The most active slopes during the storm appeared to be "repeater" slide paths that avalanched earlier in the season and the remaining snow was thin and stayed weak due to the temperature gradient metamorphism process.

The profile I dug on the flank of the Horse Canyon avalanche looked like a good example of a repeater slide path. The avalanche broke to the ground and on a very fragile layer of large depth hoar crystals. You can see more details in the video.

Because of the access issues, I'm not quite sure what to call the danger rating. It's been 4 days since the widespread avalanche cycle so, in theory, it should have settled out quite a bit. But faceted snow is one of the persistent weak layers, which makes it especially tricky and dangerous because it continues to produce avalanches several days after it's loaded with weight. At least for me, I would not be willing to jump into a steep slope that has not slide yet on one of the upper elevation, shady aspects. So I'll continue to call it Level 3 (orange) for a couple more days.

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

With continued breezy conditions for the next couple days, you will continue to find fresh wind deposits, which you should always avoid in avalanche terrain (slopes steeper than 30 degrees).

weather

Ridge top winds are blowing 20, gusting to 40 from the north with temperatures close to zero. For the next few days, we'll have clear skies, blustery wind from the north with daytime highs in the mid 20's and overnight lows in the single digits.

For the next week, we will have a high pressure ridge over us with increasingly warm temperatures.

Here's the National Weather Service link to the point forecast for the La Sal Mountains.

general announcements

Road Conditions: Geyser Pass road was plowed yesterday and is open.

Grooming: I have no information on the grooming.  I'm assuming they will groom today.

Thanks for sending in your observations. You can view Moab observations here. To post an observation go here.  You can also give me a call on my cell phone at 801-231-4744

To receive this advisory by email go here.

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.