Salt Lake Avalanche Advisory

Forecaster: Drew Hardesty

SPECIAL ANNOUNCEMENT

UDOT in Big Cottonwood Canyon will have intermittent closures tomorrow from 8-10am as they sight in their artillery for the Stairs Gulch/Storm Mountain slide paths.


BOTTOM LINE

Danger by aspect and elevation on slopes approaching 35° or steeper.
(click HERE for tomorrow's danger rating)


Danger Rose Tutorial

POCKETS OF CONSIDERABLE remain in an otherwise MODERATE landscape. The likelihood of triggering 1-3’ deep 200’ wide avalanches is mostly confined to the steep, northwest through northeasterly facing slopes above about 9,500’. Consequences of getting carried in one of these slides remain severe, even if you’re not buried.

Safer terrain does exist - slopes less steep than about 33 degrees that are not connected to steeper slopes directly above or to the sides, and slopes without the layer of buried facets – generally those at mid and lower elevations and those facing the south ½ of the compass.


CURRENT CONDITIONS

Looks like we were able to squeeze a few more inches out of the “storm” yesterday – most areas picked up another 2-4” with upper Little Cottonwood “raking” in another 6”. Densities averaged 8-10%. Winds are generally light and westerly, even along the most exposed ridgelines. Temperatures are in the mid 20s up high, the mid-teens down low. RH (relative humidity) remains high – likely we’re starting to see some surface hoar development on the snow surface. Riding conditions remain fair and thin with now enough new snow to make you think you can get down the south facing terrain.


RECENT ACTIVITY

While the new snow produced some minor sluffing and very shallow soft slab development up high, we had no new reports yesterday of collapsing or avalanches into the older, faceted snow from late October/early November. I went to look at the reported slide in the East Bowl of Silver Fork and found that Saturday’s slide pulled down into the sugary faceted snow a couple feet deep, propagating perhaps 200’ wide. It reportedly pulled out way above the snowboarder who triggered it; he was able to jet off and avoid being engulfed by the slide.

This adds up to five human triggered avalanches – and some very close calls - in this layering since Saturday (ostensibly with the additional loading from the storm). Four of the five avalanches were triggered well below from where the avalanche released. These fell into the suspect geographical pattern of northwest to northeast facing terrain above 9500’.

Details can be found on the avalanche list, at Current Conditions – Avalanche List.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

While we had no evidence of a cranky snowpack yesterday, snow data suggests we’re far from being out of the woods. It is likely that once again, the interface between the slab – the ‘cohesive plate of snow’ and the weak sugary facets below are starting to adjust and become less reactive. The double edged sword of things becoming less widespread and sensitive it that a) you’ll often have conflicting stability test results and b) your patience may wear thin. How long is long enough? This current structure may last weeks, perhaps longer. With a “bleak” outlook for storms on the horizon – these weak layers are likely to become weaker and weaker.

Inconsistent test result feedback, continued potential for unmanageable 2-3’ deep avalanches breaking away above you, and consequences of getting rag-dolled through the shallowly buried stumps and rocks dictates extreme caution if you’re willing to play the game at all.


THREAT #2

WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Most of the shallow instabilities have likely settled out overnight, but watch for continued minor sluffing in the new low density snow. Even a bit of loose snow that knocks you off your feet could be enough for an early season injury.


THREAT #3

WHERE PROBABILITY SIZE TREND
No danger rose available.
      Over the next 24 hours.

It's a good time to practice with your avalanche transceiver (to include deep and multiple burials), advanced probing and shovelling techniques. Consider the new safety technologies of avalanche airbags. Reread Bruce's book Staying Alive in Avalanche Terrain or Fredston and Fesler's updated edition of the classic Snow Sense.


MOUNTAIN WEATHER

High pressure builds into the state and we’ll see sunny skies, light westerly winds, and temperatures spiking toward the upper 20s and low 30s at 10,000’. Mountain temperatures warm above freezing tomorrow and by Wednesday night the southwesterlies begin to push into the 30-35mph range. The northern component of a splitting storm moves through late Friday, offering cooler temps and a few more inches of snow. The ridge of high pressure rebuilds soon thereafter. Things indeed look bleak through at least the first week of December.


GENERAL ANNOUNCEMENTS

If you trigger an avalanche in the backcountry - especially if you are adjacent to a ski area – please call the following teams to alert them to the slide and whether anyone is missing or not. Rescue teams can be exposed to significant hazard when responding to avalanches, and do not want to do so when unneeded. Thanks.

Salt Lake – Alta Central (801-742-2033)

Ogden – Snowbasin Patrol Dispatch (801-620-1017)

Provo – Sundance Patrol Dispatch (801-223-4150)

Dawn Patrol Forecast Hotline, updated by 05:30: 888-999-4019 option 8.

Daily observations are frequently posted by 10 pm each evening.

Subscribe to the daily avalanche advisory e-mail click HERE.

UDOT canyon closures UDOT at (801) 975-4838

You have the opportunity to participate in the creation of our own community avalanche advisory by submitting avalanche and snow observations. You can also call us at 801-524-5304 or 800-662-4140, or email by clicking HERE

Donate to your favorite non-profit – The Friends of the Utah Avalanche Center. The UAC depends on contributions from users like you to support our work.

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.

We will update this forecast tomorrow morning. Thanks for calling.


This information does not apply to developed ski areas or highways where avalanche control is normally done.  This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.


This advisory provided by the USDA Forest Service, in partnership with:

The Friends of the Utah Avalanche Center, Utah Division of State Parks and Recreation, Utah Division of Emergency Management, Salt Lake County, Salt Lake Unified Fire Authority and the friends of the La Sal Avalanche Center. See our Sponsors Page for a complete list.