Avalanche Awareness - part 358

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Avalanche Awareness - part 358

Postby Marc_C » Tue Mar 17, 2015 6:02 pm

A recent visitor on a warm day at Alta was grousing a bit about ASP not opening at least Main Chute on Baldy, assuming that if it was that warm and with spring conditions, the snowpack is stable - "If it's this warm there's no reason not to open Main". I tried to explain but it fell on unlistening ears. Below excerpts are from today's SLC avi advisory:

Areas of CONSIDERABLE danger exist in the mid and upper elevation northwest to east facing terrain for wet loose and wet slab avalanches. Human triggered wet slabs 1-3' deep remain possible. Remember it's more difficult to get untangled from flowing wet avalanches and they set up like concrete in the deposition zone. Elsewhere the danger is MODERATE.

When avalanche concerns turn toward the spring cycle, I commonly look to connect with the snow safety folks along the Park City ridgeline. Always good to share thoughts and concerns with the folks there - as PC terrain tends to be the bellwether for early wet avalanche issues. Thanks to Colin Wilkinson, Dave Weiss, and Andy Van Houten of PC snowsafety as well as Paul Santana from the Canyons for good discussion about our current situation.

As we skinned and sometimes booted through the sage from Jupiter to 9990' yesterday, Canyons snowsafety called to relay that a lone skier without avalanche gear triggered, was caught in, and lost a ski in the Canyons periphery of Dutch Draw. In an area called Conehead on a steep east-northeast facing slope at 9500'. The initial wet loose slide quickly stepped down into a wet slab pocket 2' deep and 40' wide. It was the same location of a fatality in January 2005.

It's a combination of cloud cover, wind, and temperatures that are both complex, spatially variable, and may also vary just a few miles or so along the range (due to inconsistencies of the aforementioned weather parameters).

While most of the snow we looked at yesterday was isothermal, we found wet grains along the interfaces of both the mid-February facets as well as at the top of the early season depth hoar. We also found percolation columns, the "piping and plumbing" of the spring snowpack, that allow for free water to move through areas of homogenous slabs...though the water often pools along crusts and at the interface from strong snow to weak snow. Some water/wet grains are ok...too much water is not - and this is well mirrored by the pockety wet slab activity over the past couple days.

The take-home info - even with a superficial refreeze, the engine below is still sputtering. Your skis, board, or sled may briefly keep you briefly above the snow, but without you'd be post-holing in many places without their help. I'd avoid all steep west to north to southeast facing terrain today until cooler temps arrive to lock up the snowpack. Or anyplace you find yourself in unsupportable or collapsing snow.

Especially avoid terrain traps later in the day such as gullies with steep walls or larger avalanche paths that funnel into them
Glide avalanches could occur any time of day especially in places like Stairs Gulch, Broads Fork and Mill B South
Cornices tend to sag and break off during periods of prolonged heating.
Percolating melt water may reactivate buried layers of faceted snow on the traditionally cold and shady aspects like NW, N, NE and E facing slopes at upper elevations.
-marc
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Re: Avalanche Awareness - part 358

Postby Admin » Tue Mar 17, 2015 7:16 pm

Marc_C wrote:A recent visitor on a warm day at Alta was grousing a bit about ASP not opening at least Main Chute on Baldy, assuming that if it was that warm and with spring conditions, the snowpack is stable - "If it's this warm there's no reason not to open Main". I tried to explain but it fell on unlistening ears.


Said visitor's significant other herself noted this level of ignorance and brought it up with me on her own. Same visitor reacted to my offer to take Avalanche 1 last year with the response of, "Why would I lose two ski days to do that?"
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Re: Avalanche Awareness - part 358

Postby Tony Crocker » Fri Mar 20, 2015 12:13 pm

I did not read any Utah Avalanche reports during Iron Blosam Week because I had no intention of leaving resort area boundaries. So I appreciate MarcC filling me in on that.

Given low tide conditions and numerous extended dry spells this winter I would not have expected anything from top of Baldy to be open at Alta. However, on March 8 sizable moguls were visible in Main Chute indicating it had been open at least one and probably more days since the last storm of March 3-4. In past seasons with spring conditions Main Chute was often open on the warm days (like March 7, 13 and 14 this year) and closed on cooler or windier days (like March 8-12 this year). So it was only in the context of seeing that Main had been open a week earlier that I asked the question.
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Re: Avalanche Awareness - part 358

Postby Admin » Fri Mar 20, 2015 5:01 pm

Tony Crocker wrote:I did not read any Utah Avalanche reports during Iron Blosam Week because I had no intention of leaving resort area boundaries. So I appreciate MarcC filling me in on that.


That's not a reason to not read it. However:

Tony Crocker wrote:In past seasons with spring conditions Main Chute was often open on the warm days (like March 7, 13 and 14 this year) and closed on cooler or windier days (like March 8-12 this year). So it was only in the context of seeing that Main had been open a week earlier that I asked the question.


Had you taken Avi 1 last winter as suggested, you might have actually figured it out on your own. Imagine that!

Given the level of blissful ignorance I've seen you exhibit in the sidecountry, combined with the frequency with which you like to ski outside of controlled ski resorts, I continue to implore you to educate yourself. "Why would I want to lose two ski days?" is a wholly inappropriate response. In your current state of knowledge you're not only a danger to yourself, but also to other skiers near you.
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Re: Avalanche Awareness - part 358

Postby jimk » Tue Mar 24, 2015 11:09 am

I took a 2-3 hour scenic drive on March 18 around Colorado high country; Silverthorne to Breck to Leadville to Ski Cooper to Camp Hale to Red Cliff to Minturn, past Vail, Copper and back to Silverthorne. Interesting drive. I have been in the area much of the last two months and for the first time on this scenic drive there was an obvious and widespread number of slides/avalanches visible from the back roads and beside Interstate 70. This was around the same day as the big slide in Highland Bowl. Clearly the extended warm streak destabilized things. I skied David's Run at Arapahoe Basin earlier this month, but all this recent avi activity gives me a bit of pause about doing it again given what happened to its namesake during another warm period 8-[ Today the temps are at least temporarily much cooler and it has always been at or below freezing at night so I suppose minimal worries inbounds.
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