In partnership with: Utah Division of State Parks and Recreation, The Friends of the Utah Avalanche Center, Utah Department of Emergency Services and Homeland Security and
“keeping you on top”
March 13, 2008 7:30 am
Good morning, this is Evelyn Lees with the
Ahead of an approaching storm, skies are mostly cloudy this morning. Mountain temperatures are in the low to mid 20‘s, with a scattering of teens along some of the highest ridges. The winds are from a west to southwesterly direction, with most stations averaging 10 to 15 mph, with gusts into the 20’s. The most exposed terrain has wind speeds in the 20’s, and gusts into the 30’s. Today’s new snow will be falling on patches of soft, recrystalized powder on some mid and upper elevation shady slopes, with a mix of mostly supportable crusts on the other aspects and all lower elevation slopes.
Snow and Avalanche Discussion:
No avalanche activity was reported from the backcountry yesterday.
With 3 to 6” of new snow expected today, it will become possible for people to trigger new snow slides on steep, wind drifted slopes by afternoon. Of most concern are slopes facing northwest, north and northeast at the mid and upper elevations because many have a surface layer of weak, sugary faceted crystals. In many locations, this weak layer is thick enough that even if the surface facets have lost some of their snap, weak crystals below haven’t. Where the facets are underlain by old, hard wind slabs, giving the classic “weak layer on a good bed surface”, any slide triggered has the potential to run faster and further than expected. Wind drifted slopes will become sensitive first. The “off aspects”, east and west facing slopes, have facet crust sandwiches that could complicate avalanche conditions by tomorrow if we get a foot or more of new snow.
On southeast through southwesterly facing slopes and at low elevations, the new snow will land on strong melt freeze crusts, and the only problem today will be on heavily wind drifted slopes.
Bottom Line for the
The avalanche danger is LOW this morning. As storm snow accumulates, especially this afternoon, the danger will rise to MODERATE on steep northwesterly through easterly facing slopes, mainly on slopes with drifts of wind blown snow. It will become possible for people to trigger soft, new snow avalanches on these steep shady slopes, and some of these slides may run faster and further than expected.
A moist, west to northwesterly flow will be over northern Utah the next few days, with a series of fast moving weather disturbances bringing periods of snow. A few snow showers are possible this morning, followed by periods of heavier snow this afternoon and tonight. 3 to 6” of snow is expected today, with totals of about a foot possible by Friday noon. The winds will be increasing throughout the day, from the southwest this morning, shifting to the northwest this afternoon. Wind speeds will reach the 20 to 30 mph range by afternoon, with the highest peaks having gusts into the 50’s and 60’s. Temperatures will start out in the 20’s and 30’s this morning, cooling into the teens at 10,000’ by evening. The weekend looks like it will be mostly cloudy, with small amounts of additional snow possible.
Head’s up: This Saturday morning, the Black Diamond Wasatch Powderkeg race will have lots of huffing-and-puffing racers in Grizzly Gulch near Alta from about 7:00 am to noon.
The Wasatch Powderbird Guides did
not fly Wednesday due to weather, and will probably not fly today. If they do get out, they will have one ship in
Mineral, Cardiff Days, Silver,
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UDOT highway avalanche control work info can be found by calling (801) 975-4838.
Our statewide tollfree line is 1-888-999-4019 (early morning, option 8).
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If you see any avalanches or interesting snow conditions, please leave us a message at (801) 524-5304 or 1-800-662-4140, or email us at [email protected]. (Fax 801-524-6301).
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.
Brett Kobernik will update this advisory by 7:30 on Friday morning.