UPDATE: Sunday, April 30, Alta Ski Area is OPEN to uphill traffic
We have stopped issuing regular avalanche advisories for the 2016/2017 season. For the rest of the month we will issue Friday updates for the central Wasatch Mountains and updates any time there is measurable snowfall; however, we have discontinued issuing avalanche danger ratings altogether.
At 6 am on Saturday mountain temperatures are in the low to mid teens and winds are out of the north/northeast, gusting into the 20's mph at low and mid elevations, and the 30's mph at 11000'. Overnight snow totals are 3" in both Big and Little Cottonwood Canyons, adding to the 8" that fell during the day on Friday.
Approximate storm totals this past week are 18-48" with over 4.5" of water, with Little Cottonwood Canyon on the higher end of snow and water totals.
Week in Review
Perhaps Ullr is thanking us for our perseverance the past several seasons as the last week of April delivered Winter 2.0:
Friday April 21 featured 8" of snow in the Cottonwoods with minor sluffing and small, wet-loose activity reported.
Saturday brought an extended period of east winds and cool temperatures with several skier-triggered slides from fresh wind drifts in the upper elevations.
Sunday included wet loose activity as the sun warmed the snow surface.
Snowfall began on Monday and continued well into Tuesday. Storm totals at Alta totaled 26" with 2.6" of water. Snowfall rates of 3-4" per hour were observed in upper Little Cottonwood Canyon, generating an early-morning natural cycle with several natural as well as skier-triggered avalanches running at the new snow/old snow interface.
As is often the case in the Spring, by Wednesday conditions rapidly settled out with only minor wet loose activity reported.
Snowfall began overnight Wednesday into Thursday, with 10" of snow in LCC, and about half that amount in BCC and the Park City ridgeline. This storm featured strong northwest winds that created sensitive wind slabs in the mid and upper elevations, with several human-triggered avalanches reported. The largest reported slide was on a SE aspect in Cardiff Bowl, and over 1000' wide.
Friday remained cold with up to an additional 8" of very low-density snow and reduced winds.
Snow depths are up to 160" in upper Little Cottonwood and 136" in upper Big Cottonwood (elevations 9600') . The Ogden mountains still boast 90"-105" (8000' elevation sites) and the Provo mountains have 100" at 8800' elevation. The Alta Guard broke 500" during Tuesday's storm for the 18th time since 1944 and the first time since 2010/2011. Alta Guard monthly snowfall can be found here.
For more information:
- Weather stations and wind sites click HERE.
- Weather forecast and discussion click HERE.
- NOAA snow and avalanche page click HERE.
Observers on Friday noted sluffing in the top few inches of the very low-density storm snow as well as some minor wind drifts just along the ridgelines. Although most found instabilities with Thursday's wind slabs to have settled out, there were two reports of unintentional, human-triggered wind slab avalanches on Friday:
- East aspect at 9400' on Murdock Peak
- Southeast aspect at 10000' on Little Superior
Both slides were reported to be 12" deep and breaking out 60' wide.
Full list of reported avalanches HERE
Other observations HERE.
Although we will be shutting down regular operations, we will continue to post recent avalanche activity and observations, so please do continue to send them to us. You can check the latest observations here. We also follow avalanche-related activity on Instagram - be sure to tag your photos with #utavy .