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Wasatch Avalanche Conditions

Regional discussion and conditions reports for the great state of Utah, from the alpine peaks to the desert slots. Please post partners requests and trip plans here or in the Utah Climbing Partners section.
 

Postby TyeDyeTwins » Mon May 24, 2010 2:45 am

Observation May 23 Went up to Clayton Peak today. From the summit we skied the Northeast Chute. About 5 turns in I triggered a small/shallow wind slab that ran most of the way down the run. When my partner dropped in after me he triggered the rest of the hangfire. Had the windslab been 2 feet deeper it could have been a serious avalanche. On the way up to Peak 10,420 from what is known as "Lackawaxen Basin" we heard several whoomphs and felt several collapses. From the summit of Peak 10,420 we could see another shallow wet slab avalanche that ran on the dirt layer. It was located on the East Facing slopes of Twin Lakes Pass and it was not there this morning. We saw a rainbow in the sky on our way out from Clayton Peak.....a sign of moisture to come?

Despite the shallow wind slab that we triggered today the avalanche danger was still LOW. Tomorrows avalanche danger will all depend on just how much snow we actually get out of this storm. Weather gussers are calling for 4-8 inches tonight followed by 3-5 inches tomorrow. With the combination of wind and new snow tomorrow could easily reach the MODERATE catagory in the steeper, more avalanche prone slopes of the Wasatch Range.

The 1st picture is of Troy skiing down Clayton Peak's Northeast Chute after I triggered a small and shallow wind slab
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The 2nd picture is of the rainbow in the sky we saw on our way out of Clayton Peak
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Postby TyeDyeTwins » Wed May 26, 2010 4:04 am

Observation May 25 Had some very close calls with avalanches out there today. Troy and I started by skinning Twin Lakes Pass from Brighton early this morning. We broke trail from the lake to the pass. Just as Troy and I reached the pass a wet avalanche came off of the "Highway to Heaven" slide path, stopping just before our skin track. We decided to ski the East Bowl in Silver Fork. Got 1st tracks with no incident. As we went to skin up to Flanningans we heard over 15 whoooomphs and felt many more collapses (a new season record for us). At the top of Flanningans we dug a snowpit. We found 2 inches of light powder with 2 inches of crust all sitting above a perfectly soft perserved powder layer. This layering was responsible for the whoomphing/collapsing. Judging by our snowpit we abandoned the thought of skiing the Spillway Chute (hanging snowfeild above a 70 foot cliff) and we went to ski a shot on Flanningans that we knew (from past expirence) we could successfully slope cut safely if it did avalanche.

With the camera set up Troy came in to make his 1st turn on the steep chute. About 4 seconds after his turn I heard a whooomph and watched the slope break apart. As I went to have a closer look, the large avalanche grew and grew as it approached the trees. At the avalanches maximum I was praying that Troy was not in the slide somewhere. By the time I switched my beacon to search I heard a BOO (the signal that everything is ok) in the forest off to the side of the slide path. I decided to decend right on the avalanche bed surface to get down safely. The bed surface was like skiing fine dust on crust.....a perfect avalanche layer.

This avalanche occured around 1pm on a steep (+35 degrees) Northwest Facing slope at about 10,200 feet. The avalanche crown was 5-7 inches and the slide ran almost 900 vertical feet into the trees. The debrie pile was about 1 to 2 deep and was about 250 feet wide. Avalanches like this are not usually a concern for late May but as it has been said a 100 times already this season.....this is not your average year out there in the Wasatch. Today's avalanche danger was definately in the CONSIDERIBLE catagory by the afternoon........Wasatch your back out there tomorrow.

The 1st picture is of Troy making his 1st turn in Flannigans that started the avalanche
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The 2nd picture is of the avalanche from the top of the slide path
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The 3rd picture is looking up at the path from near the toe of the debrie pile. Not all of the debries are pictured.
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Postby TyeDyeTwins » Sat Jun 05, 2010 5:07 am

Observation June 4 We have been in Great Basin National Park for a while so we went up to Bountiful Peak today to get a handle on how the Wasatch Range is doing. The road in Farminton Canyon was still closed at 7,200 feet (should have opened 4 days ago) so the climb was a lot longer than expected. The snow line was around 8,800 feet and even though there was no such thing as a refreeze, the snowpack was in a summer time state. The cornices up near the summit were huge and had melting water as well as cracks from where there are starting to give way. The skiing was far from epic but it what do you expect in June?

The avalanche danger where we traveled today was in the LOW catagory. Avalanche wise we are approaching the days where summer rules apply (stay back from cornices, watch for rock fall, avoid narrow couloirs in the afternoon, and be cautious of the infamous wet slab concern in the most extream of terrain.)

The 1st picture is of Troy skiing Bountiful Peak today.
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Postby WhitePine » Mon Jun 07, 2010 4:21 pm

So, considering that we are in summer-time conditions now and a refreeze is non-existent, how does one assess whether a slope is safe or not?
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Postby TyeDyeTwins » Tue Jun 08, 2010 6:38 pm

For something to be "safe" in the summer time is dependent on serveral factors but there are 3 that are considered the most important........

1. THE PLUMBING- Whether a slope has good plumbing is the most important aspect of summer skiing. In places where the water underneath the snowpack is spread out amoungst the whole slope is what you should be looking for. Evidence of these conditions taking place is runells in the surface snow. These slopes are a lot safer than places where the water focused into a small area (huge gullies, some couloirs ect....). The most dangerous slopes are those that collect water into pools that dam up. When the water finally breaks loose it can cause huge wet slab avalanches late in the year.

2. THE SNOWPACK DEPTH- Suncups are a good indicator of settlement on the surface. To find out what is underneath a snowpit works the best. If you see signs of water running through the snowpit you there should be a red flag going through your mind. The total snow depth this time of year is elevation dependent. The lower you go the safer it will be because the lower elevations are not being "shocked" by new high temps. When the highest elevations get there 1st taste of summer time temps there is an increased risk for avalanches as well as rock fall. Sometimes the early season depth hoar burried deep down reactivates when it gets wet and causes huge avalanches. This type of avalanching has occured in the past in places such as Scotts Bowl @ Park City and Gobblers Knob's Cabin Run. The best advice......get up and get out early before the sun melts more danger. Also it helps to dig serveral snowpits along the way.

3. THE BED SURFACE- The most tricky of all avalanche evaluations in the summer time is what is on the bed surtace. The best way to know what is underneath all of the snow is to see the slope in the summer time. Places where there are no trees and it is nothing but loose shale, grass or just a rock slab are poor bed surfaces to be skiing on. These areas tend to not hold the snowpack back and allow water to run along the ground level with not a lot of resistance.

I hope you find some of this information handy. Happy Trails out there.
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Postby Ed F » Tue Jun 08, 2010 8:42 pm

Totally agree with everything TyeDye said. Great advice.

I'll add a few things:
Wet slabs occur and release mostly from three things: (1) water lubricating a sliding surface, especially if the sliding surface is impermeable to water (rock, ice, etc.) (2) loading by rain precipitation and (3) reduction in strength of a buried weak layer due to percolating water.

Digging a pit is really helpful to see what's going on underneath the snowpack. Otherwise, rollerballs are great clues. Another good tool is to see how deep you penetrate the snowpack with a foot. Ankle deep is yellow light, shin deep is red light. You've also got to watch the weather night after night. Three or four nights without a freeze is bad. A one night slight freeze is questionable. A two or three night freeze makes things pretty safe. Watch how high the temps get, and at what time of day, and with what % cloud cover.
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