Little Cottonwood Canyon Backcountry Closure:

LCC Full Closure North Side

Thursday, February 23, 2017 - 10:00pm to Friday, February 24, 2017 - 8:00am

Full north-side LCC backountry closure from Lisa Falls through Grizzly Gulch. South-side access from White Pine parking ok. Estimated opening when LCC road opens approximately 8am Friday the 24th.

Click here for more details.

As of 5 am, mountain temperatures range throughout the single digits and winds are out of the west/northwest. Winds increased for a few hours overnight, but are currently averaging < 10 mph with gusts in the teens at 10000'. Above 10,000' winds are averaging in the teens with gusts in the 20's mph, although gusts have been a high as 40 mph at 11,000'.

The Cottonwoods and Park City mountains picked up another 5-7" of 3-5% fluff overnight, with 24 hour totals of 18". The Week in Review summarizes snow totals for the past week.

Despite the low-density fluff, trailbreaking was a chore on Thursday, and thigh-deep in places. Settlement overnight and during the day today should help reduce the struggle of uphill - and occasional downhill - trailbreaking.

Week in Review

A series of weather systems on a southwest flow arrived over Friday through Sunday Feb 17/18/19 with storm totals of up to 24" in the Cottonwoods, 14" in the Park City mountains, 18" Ogden mountains, and 6" at the mid elevations in the Provo mountains. Storm densities were Cascade-like with water totals exceeding 2".

Sunday was an especially active day with several skier-triggered avalanches reported from the backcountry. These slides included both storm snow as well as fresh wind slabs, and were running within the storm snow as well as a layer of faceted snow that formed Feb 12-15 during a period of clear high pressure.

Monday and Tuesday featured warming temperatures, with increasingly strong winds that gusted over 60 mph by Tuesday afternoon. These strong winds ushered in a cold front that arrived Tuesday evening. A cold, unstable northwest flow led to continued moderate to strong snowfall since Tuesday evening, with impressive storm totals:

• 30-47" in LCC and BCC with 2.0" - 4.0" of water
  
• 31" Park City with 2.35" of water
  
• 34" Ogden mountains with 2.5" water
  
• 23" Provo with 1.6" of water.

Avalanche activity during this storm included wind drifts primarily at the upper elevations and long-running sluffs in the loose dry snow and resulted from control work at the resorts and the mountain highways, as well as natural activity that occurred during spikes in precipitation. During this period, the avalanche hazard was either Moderate or Considerable, but with brief spikes to High during periods of heavy precipitation.

Small to medium-sized slides were reported from control work at the resorts as well as highways on Thursday, and a few small natural avalanches were reported overnight. Late yesterday afternoon a large (class 3) natural avalanche was reported from Mount Superior in Little Cottonwood Canyon. Reports from the backcountry indicated sensitive storm snow during spikes in precipitation, with a likely natural cycle occurring in the late morning, although poor visibility limited avalanche viewing. Pro observer Mark White was able to trigger a soft slab avalanche in West Monitor Bowl along the Park City ridgeline. You can read Mark's usual excellent write-up here.

Today will be a beautiful winter day with pleasantly cool temperatures, cloudy skies, and with a cold, unstable, northwest flow* continued snow showers that may add up to 3-6". Winds are forecasted to be out of the west/northwest and average about 10 mph at mid elevations, and low 20's at the upper elevations, with temperatures rising into the teens. Continued light to moderate winds overnight with temperatures just above 0 F. Saturday should remain cool and cloudy with snow showers later in the day.

A copy-cat cold storm forecasted for early this coming week.

* With apologies to Henry James, the most beautiful words in the English language.