Advisory: Logan Area Mountains | Issued by Toby Weed for March 7, 2013 - 7:10am |
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Above 8,500 ft.
7,000-8,500 ft.
5,000-7,000 ft.
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bottom line Heightened avalanche conditions exist, there's a MODERATE (or level 2) danger in the backcountry, and you could trigger wind slab avalanches and/or cornice falls in drifted terrain. There are pockets with more dangerous, CONSIDERABLE (level 3) avalanche conditions in some drifted terrain at upper elevations today. Dangerous persistent slab avalanches are possible in outlying terrain with poor snow structure and added weight from recent incremental precipitation and drifting. Rain and warmth will soften the snow and increase the danger of wet avalanches on slopes with saturated snow, with the worst conditions in shady lower and mid elevation terrain plagued by shallow and structureless snow-cover. Evaluate the snow and terrain carefully, and continue to use safe backcountry travel protocols.
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current conditions The Tony Grove Snotel at 8400' reports 5 inches of snow in the last 24 hours containing 3/10ths of an inch of water. It's 20 degrees, and with 65" of total snow, the station sits at 64% of average water for the date. The CSI Logan Peak weather station at 9700' reports 15 degrees and northwest winds averaging around 10 mph this morning. Sustained south winds yesterday certainly drifted snow around in exposed terrain and you'll find scoured southward facing windward slopes and stiff wind slabs in more north facing deposition areas.
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recent activity We observed numerous natural loose wet avalanches from Sunday involving rain-saturated snow and gouging to the ground at lower elevations in Logan Canyon, Providence Canyon, and across the region. A skier intentionally triggered a couple nice fresh hard wind slabs with cornice drops in the Ogden Area Mountain yesterday. These were reported to be 1 to 3 feet deep and up to around 250' wide. No avalanches were reported in the Logan Area yesterday.. Here's a link to our updated Avalanche List.
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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
Drifting of Sunday's fresh snow from sustained south winds yesterday created heightened wind slab avalanche conditions, mainly at upper elevations, and pockets of dangerous conditions exist in some exposed terrain. You could trigger stiff wind slabs and/or cornice falls in steep drifted upper elevation terrain today. Watch for and avoid stiffer wind deposited snow on the lee side of major ridges and in and around terrain features like sub-ridges, cliff bands, and steep walled gullies. Ridge top cornices might break further back than expected, and cornice falls could trigger more dangerous slab avalanches on steep slopes below.
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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
Isolated persistent slab avalanches up to around 2-and-a-half feet deep, failing on weak sugary faceted snow or basal layer depth hoar are possible in outlying areas with shallow and poor snow structure. I'm not a fan of the inevitable spring warm-up, which could increase the danger of triggered persistent slab avalanches due to increased creep rates in the upper layers of the snowpack and/or softening of existing hard slab layers. The added weight from this week's drifted snow and/or rain also might be enough to activate buried dormant weak layers in some areas, and dangerous triggered avalanches are a possibility we just can't ignore. Whumpfing is a significant red flag indicating potential persistent slab instability.
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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
Rain at lower elevations increased the danger of loose wet avalanches, and you are likely to trigger wet avalanches if you venture on steep slopes with saturated surface snow.. Wet slabs are possible in areas with saturated snow and poor snow structure. Warming and continued rain today could loosen wind slabs, cornices, and persistent slabs, and increase the chances of triggering avalanches of all types. |
weather Expect some snow, mild temperatures, and moderate westerly winds today, with high temperatures at 9000' around 35 degrees and 1 to 3 inches of accumulation forecast. Mild and moist weather will continue into the weekend, with an inch or two possible each 12-hour period into Saturday morning. Expect daytime high temperatures in the mid thirties and overnight lows in the mid twenties. Clearing and sunny conditions are expected to redevelop around Sunday. Check out the Logan Mountain Weather page...
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general annoucements Go to http://www.backcountry.com/utah-avalanche-center to get tickets for Beaver Mountain. You won't save a ton of money, but all proceeds from sales of these tickets will benefit the Utah Avalanche Center, and It's super easy to do. For a printer friendly version of this advisory click HERE Remember your information from the backcountry can save lives. If you see or trigger an avalanche, or see anything else we should know about, please send us your 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. I will update this advisory on Monday, Wednesday, Friday, and Saturday mornings by around 7:30... 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. |