| Please join us at the 23rd annual Black Diamond Fall Fundraiser Party Thursday Sept 15. Tickets are on sale now here, at the Black Diamond store & at REI. Special bonus raffle for online ticket purchasers! |  |
| Advisory: Salt Lake Area Mountains | Issued by Drew Hardesty for Saturday - April 16, 2016 - 6:43am |
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bottom line We customarily do not issue danger ratings at this point in the season, but rather provide snow and avalanche information and weather forecasts. This advisory will cover the weekend and we'll continue to issue intermittent advisories over the next couple of weeks. For Saturday and Sunday, human triggered wind drifts are possible in the more wind affected terrain with the danger rising rapidly for wet sluffs and wet slabs if the sun comes out for any length of time. Remember that cracking and collapsing are immediate signs of instability. Avoid thinner snowpack areas of poorly consolidated wet snow. (This you'll know because you'll feel like you've stepped through a trap-door in the wet snow.)
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special announcement We will continue to post observations as they are especially important to the backcountry community this time of year. We may also update conditions via social media or issue Warnings if needed through the national weather service. If you see anything you feel we should know about, please submit an observation.
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current conditions Under partly to mostly cloudy skies, mountain temperatures are in the mid to upper teens. Winds are north to northeasterly with the more unobstructed anemometers along the south end of the Park City ridgeline and on James Peak in the Ogden mountains showing hourly averages of 25-30mph with gusts to 40. The more protected areas from the north to northeast winds have hourly averages at or less than 15mph. Storm totals are roughly 8-14" in the higher terrain with water amounts since the 13th (when rain fell to near 10,000') nearly 2" in the central Wasatch and nearly 3" in the Ogden mountains and what looks 1" in the Provo mountains. Skiing and riding conditions are quite good, particularly above 9000'. You can find recent observations here. The fine print for the Avalanche Problems is below. Remember you can always click the 'i' next the each Avalanche Problem info-graphic for more info. |
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recent activity Snow safety teams reported easily triggered shallow storm slabs up to 6-8" deep failing primarily on a graupel or a rimed layer a few inches above the old snow surface. One could easily discern this failure plane in simple tap tests as well. Of greater interest are the now three explosive-induced wet slab avalanches to the ground in the Cottonwoods over the past two days. The two in upper Little Cottonwood released with 4 lb air-blasts, pulling out 3-5' deep and 1-200' wide, running on damp facets near the ground. These on steep northeast facing slopes at 10,000'. Debris piles were impressive. Control teams in mid-Big Cottonwood yesterday also triggered a 3' deep and 70' wide wet slab to the ground with a 2 lb air-blast on a west facing slope at 9800'. |
| type | aspect/elevation | characteristics |
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LIKELIHOOD
 LIKELY
UNLIKELY
SIZE
 LARGE
SMALL
TREND
 INCREASING DANGER
SAME
DECREASING DANGER
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description
Wet slabs are notoriously difficult to forecast. Still - over and above the three explosive-induced wet slabs to the ground - observers continue to report isolated collapsing in the superficial melt freeze crust on the poorly consolidated wet grains below. My best guess is that one would either need to find a particularly shallow spot with nearly unsupportable wet isothermal snow or have another natural or human triggered avalanche gouge into this layering in order to produce a wet slab. |
| type | aspect/elevation | characteristics |
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LIKELIHOOD
 LIKELY
UNLIKELY
SIZE
 LARGE
SMALL
TREND
 INCREASING DANGER
SAME
DECREASING DANGER
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description
If and when the sun comes out, the snow on the steep sunlit slopes will quickly become damp and unstable. Beyond the deteriorating snow quality, natural rolllerballs, pinwheels, and sluffs will give immediate clues to increasingly dangerous conditions. Natural and human triggered wet sluffs will be quite likely with any periods of direct sun and warming temps...and can be particularly problematic in confined terrain. |
| type | aspect/elevation | characteristics |
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LIKELIHOOD
 LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
 INCREASING DANGER
SAME
DECREASING DANGER
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description
Moderate to strong north to easterly winds will produce sensitive drifts along the higher ridgelines today and perhaps more prominent along the eastern escarpment of the range. North to northeast winds are (fortunately) uncommon; the flipside is that drifts may be found in unusual terrain. Look for drifts in steep southerly to westerly starting zones and perhaps cross-loaded wind pillows in steep east facing couloirs in the higher terrain. |
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weather The storm slowly spinning over the 4-corners area will keep us under a generally cool north to easterly flow today and tomorrow. It'll kick in periods of cloud cover as it languidly moves north and east over Colorado over the next couple of days. For today, expect partly to mostly cloudy conditions with northeast winds blowing 20-25mph increasing in the afternoon. Temps will be in the upper 20s at 10,000', the upper 30s to low 40s at 8000'. Weak ridging and a warming trend for mid-week with perhaps another storm for Friday. |
general announcements
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