bruce — Sun, 29 Apr 2012 17:25:23 -0600

Special Announcement

We have ended our avalanche advisories for the season.

This does not mean the end of avalanches, nor the possibility of more avalanche incidents. But all our forecasters are off duty for the season.

But you can continue to share your own avalanche observations with others in the community through our website as usual. Just click on the Submit Observation link on our home page and you can read the observations from others in the Current Conditions off the main menu.

Also, remember that the closed ski areas are not doing any avalanche control so those slopes that usually have moguls are now potentially dangerous avalanche terrain and you have to do your stability evaluation and safe travel practices just like any other backcountry avalanche terrain.

In the sections below, I have outlined some general strategies for avoiding spring avalanches. But first....

We would like to say thank you, thank you, thank you to everyone who contributed to your community avalanche center, especially all of you who sent in observations of avalanches and general conditions. The more we share our information, the safer we are.

Last, but not least, we would like to especially thank everyone who contributed to the funding of our community avalanche center. We are a Forest Service program but over 3/4 of the funding comes from other partners. This includes: all of your donations through Friends of the Utah Avalanche Center, Utah Division of State Parks and Recreation, Utah Public Safety, Salt Lake County, Black Diamond, Backcountry.com, all the ski areas that donated lift tickets, Ski Utah, Unified Fire Authority and the various shops that donate snowmobiles and other equipment such as Polaris/Tri-City Performance, Weller's Recreation/Ski Doo and Arctic Cat/Big Pine Sports, Recco, Wasatch Backcountry Rescue, Back Country Access and ABS. Whew! Forgive me for anyone I have forgotten. As you can see, we have lots of support and we are the epitome of a successful partnership organization--thanks to you.

We should have our annual report done soon, which you can find in the Archives section.

Current Conditions

In our absence, you have a plethora of great information on current conditions:

Snow Page (from the National Weather Service) is one-stop shopping for most everything you will need to know about mountain weather.

SNOTEL Map (from NRCS)

Satellite Imagery (scroll down and click on Infrared > Western US > 2km > Animation)

Radar Imagery (click on the Composite Reflectivity > Loop)

Recent Activity

Visit the Current Conditions section of our web page to view posts by others of avalanche activity and general observations.

Threat #1

Threat:	New Snow
Where:
Probability:	None
Size/Class:
Trend:	None over the next 24hrs.

Each spring, avalanche conditions generally become more predictable and our avalanche advisories end up repeating themselves like a broken record. So here is the usual spiel:

As my 95-year-old Czech mother-in-law reminds me, “Spring is always a fight between winter and summer.” We have alternating, cold, dry powder storms followed by warm, sunny weather that quickly turns the snowpack soggy.

First for storm snow: we have to worry about the usual round of avalanche activity that occurs during storms, namely instabilities within the new snow and wind slabs. Luckily, in spring, the new snow usually falls on a very stable pre-existing snowpack, so all the monkey business is near the surface. Be sure to use your usual round of tricks like jumping on small test slopes to see how they respond and dig down with your hand to see how well the snow is bonded. Also, you should never commit yourself to a slope without first putting a good slope cut across the slope to test it. If the slope fractures, hopefully, your momentum will take you off the moving slab. And as always, avoid steep slopes with recent wind deposits.

Threat #2

Threat:	Wet Avalanches
Where:
Probability:	None
Size/Class:
Trend:	None over the next 24hrs.

Between storms, the new snow turns soggy in a hurry with warm temperatures and strong spring sun. Always avoid steep, sun-exposed slopes when they begin to turn wet for the first time. They will often produce roller balls or pinwheels as a precursor to producing larger, wet or damp sluffs.

Second, watch for several unusually warm days in a row because percolating melt water can lubricate and weaken deeply buried weak layers, which produce large, dangerous, wet slabs. We often see these occur during very warm weather after 2 or 3 nights of no freezes or limited freezes, especially on a layered, winter-like snowpack, which has not experienced percolating melt water before. When playing on corn snow (melt-freeze snow) be sure to get out early and head home early—before the snow surface gets punchy. This year, especially, we have buried layers of faceted snow still left over on the upper elevation northerly facing slopes and they are always the last to produce large, wet slab avalanches. These will be difficult to trigger but they are very large and destructive.

Third, you need to avoid snow resting on steep, rock slabs, which often produce glide avalanches in which the entire snowpack moves slowly like a glacier until it releases catastrophically. These releases can occur any time of day and counter intuitively seem to release more in the early morning hours, just when you expect it the least. In the Salt Lake mountains, glide avalanches occur like clockwork in places like Stairs Gulch, Broad’s Fork and Mill B South, which are always good places to avoid in spring.

Mountain Weather

Luckily, we also have an embarrassment of riches when it comes to weather forecasting. Here are some links we use regularly:

Graphical forecast for Alta (You can click on any mountain location you want by using the map, which generates a forecast for where you click.)

To get fancy – and – if you know how to read weather maps…

Penn State

U of U time-height sections for SLC (Click on the time on the upper left to display the graph. Time is on the bottom axis and height in the atmosphere on the vertical axis—well—you just have to stare at it until it makes sense, but it’s extremely powerful.)

UDOT canyon closures UDOT at (801) 975-4838

Donate to your favorite non-profit –The Friends of the Utah Avalanche Center.The UAC depends on contributions from users like you to support our work.

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.

Overall Danger Rating

None

Bottom Line Solid:

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

Bottom Line Pockets:

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

Threat 1 Solid:

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

Threat 1 Pockets:

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

Threat 2 Solid:

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

Threat 2 Pockets:

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

Threat 3 Solid:

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

Threat 3 Pockets:

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

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We have ended our avalanche advisories for the season.

This does not mean the end of avalanches, nor the possibility of more avalanche incidents. But all our forecasters are off duty for the season.

In the sections below, I have outlined some general strategies for avoiding spring avalanches. But first....

We should have our annual report done soon, which you can find in the Archives section.

[announcement_general] =>

UDOT canyon closures UDOT at (801) 975-4838

Donate to your favorite non-profit –The Friends of the Utah Avalanche Center.The UAC depends on contributions from users like you to support our work.

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.

[conditions_current] =>

In our absence, you have a plethora of great information on current conditions:

Snow Page (from the National Weather Service) is one-stop shopping for most everything you will need to know about mountain weather.

SNOTEL Map (from NRCS)

Satellite Imagery (scroll down and click on Infrared > Western US > 2km > Animation)

Radar Imagery (click on the Composite Reflectivity > Loop)

[activity_recent] =>

Visit the Current Conditions section of our web page to view posts by others of avalanche activity and general observations.

[weather_mountain] =>

Luckily, we also have an embarrassment of riches when it comes to weather forecasting. Here are some links we use regularly:

Graphical forecast for Alta (You can click on any mountain location you want by using the map, which generates a forecast for where you click.)

To get fancy – and – if you know how to read weather maps…

Penn State

[threat_problem_1] => New Snow [threat_problem_2] => Wet Avalanches [threat_problem_3] => None [threat_probability_1] => None [threat_probability_2] => None [threat_probability_3] => None [threat_size_1] => None [threat_size_2] => None [threat_size_3] => None [threat_trend_1] => None [threat_trend_2] => None [threat_trend_3] => None [threat_assessment_1] =>

Each spring, avalanche conditions generally become more predictable and our avalanche advisories end up repeating themselves like a broken record. So here is the usual spiel:

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Utah Avalanche Center - Salt Lake