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Advisory: Logan Area Mountains | Issued by Toby Weed for December 21, 2012 - 7:08am |
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![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Above 8,500 ft.
7,000-8,500 ft.
5,000-7,000 ft.
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bottom line The overall danger is MODERATE (level 2), and you could trigger wind slab and/or dangerous persistent slab avalanches on steep drifted slopes in the Logan backcountry today. There are also localized areas with a CONSIDERABLE (or level 3) danger at upper elevations on slopes with recent deposits of drifted snow facing the northern quarter of the compass, where triggered avalanches are probable. Avalanches in some areas might be triggered remotely from a distance or below. Evaluate the snow and terrain carefully, and continue to make conservative decisions regarding your route selection.
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current conditions The Tony Grove Snotel reports 47 inches of total snow, 96% of average water content for the date, and it's 20 degrees at 8400' this morning. Campbell Scientific's 9700' Logan Peak weather station reports sustained southwest winds overnight and gusts above 50 mph early this morning. The surface of the fresh snow from earlier in the week is now re-crystallized, and it's pretty fast. and supportable in the upper layers. We're only sinking in around 6 inches into nice powder on the sled and skis, but as soon as you dismount you sink to your thighs in soft snow. Trail breaking is much easier than expected, and you can find very nice smooth and fast shallow powder conditions....
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recent activity We've been seeing evidence of widespread natural avalanche activity from Monday's intense storm across the Logan Zone on upper elevation slopes facing northwest through east. Two natural avalanches, triggered by rapid wind-loading were reported in the Central and Southern Wasatch yesterday. |
type | aspect/elevation | characteristics |
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![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Above 8,500 ft.
7,000-8,500 ft.
5,000-7,000 ft.
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description
Triggered wind slab avalanches are probable on steep drifted slopes today. Stiff wind slabs formed yesterday and overnight from sustained south winds at upper elevations. Watch for and avoid stiffer wind deposited snow on the lee sides of major ridge-lines and in and around terrain features like gullies, scoops, sub-ridges, cliff bands, and rock outcroppings.. Winds slabs will appear smooth, rounded, and maybe chalky, and they often sound hollow or drum-like when you walk around on them. Today you might find very sensitive slabs, potentially releasing from remote triggers, or more stubborn slabs that might wait for you to get out on them before releasing....
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type | aspect/elevation | characteristics |
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![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Above 8,500 ft.
7,000-8,500 ft.
5,000-7,000 ft.
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description
There are areas with poor snow structure where you might trigger dangerous and broad slab avalanches releasing on buried persistent weak layers. I've been observing weak layers consisting of small sugary grains called faceted snow across the zone, with the weakest in areas with relatively shallow snow. I'm most concerned about areas where the fresh slab is thinner, on windswept rocky slopes or mid elevation shady slopes that were holding a bit of old faceted November snow.. Areas with shallow weak snow that are also drifted-in by yesterday's and last night's south winds are suspect. Hard slab avalanches in some areas might be triggered remotely from a distance, or worse, from below. Pay close attention to red flags like audible collapsing and cracking, and always be willing to reevaluate or turn back.
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weather The breezy and mild southwest flow will continue through the weekend. It will be partly sunny today, with mountain high temperatures near 30 degrees and a sustained southwest breeze on the ridges. A weak storm will cross northern Utah Saturday night, and we could pick up an inch or two of accumulation. A stronger storm system will impact much of Utah and southern Wyoming late Sunday through Monday. Check out the Logan Mountain Weather page...
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general annoucements The friends of the Utah Avalanche Center in Logan is presenting an Advanced Skills backcountry 201 class in early January. A classroom session on the evening of January 3 and a field day on Saturday January 5. Here's a link for more information and registration; Advanced Skills, backcountry 201 or call 435-757-2794. Discount lift tickets are in and it would be a good day for lift serviced riding! Go to http://www.backcountry.com/ The Friends of the Utah Avalanche Center in Logan have a two person pass for a day of powder skiing or riding with Park City Powder Cats, and they're opening this weekend. If you are interested in a good deal for a memorable powder experience call Paige at 435-757-2794.... Remember your information can save lives. If you see or trigger an avalanche in the backcountry or see anything else we should know about, please participate in the creation of our own community avalanche advisory by submitting snow and avalanche observations. You can also call us at 801-524-5304 or email by clicking HERE. In the Logan Area you can contact Toby Weed directly at 435-757-7578. This advisory is produced by the U.S.D.A. Forest Service, which is solely responsible for its content. It describes only general avalanche conditions and local variations always exist. |