Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Sunday - December 21, 2014 - 7:15am
bottom line

The danger will rise to HIGH (level 4) by this afternoon, with increasingly strong west winds, warming temperatures, and heavy snowfall. Very dangerous avalanche conditions are developing, with natural and triggered avalanches becoming more likely as the day progresses. Avoid travel in avalanche terrain. Stay off of and out from under steep slopes and obvious or historic avalanche paths.




avalanche warning

A WARM WINTER STORM WITH HEAVY SNOW AND STRONG WINDS WILL MAKE AVALANCHE CONDITIONS INCREASINGLY DANGEROUS THROUGH MONDAY. HUMAN TRIGGERED AND NATURAL AVALANCHES WILL BE LIKELY TODAY THROUGH MONDAY ON STEEP TERRAIN ABOVE 8000 FEET. RAIN BELOW 8000 FEET MAY PRODUCE UNSTABLE AVALANCHE CONDITIONS AT LOWER ELEVATIONS AS WELL. PEOPLE SHOULD AVOID BEING ON OR BELOW ANY STEEP SNOW COVERED SLOPES UNTIL AVALANCHE CONDITIONS IMPROVE.

current conditions

The 8400' Tony Grove Snotel reports around 8 inches of snow containing 1.4" of water in the last 24hrs. The station reports 46 inches of total snow containing 104% of average water for the date, and it's 28 degrees. West winds are cranking up canyon, with the UDOT Hwy 89 Logan Summit weather station reporting average wind speeds in the mid 20s with gusts in the mid 30s. Increasingly strong west winds and continued heavy snowfall today will create dangerous conditions and a rising avalanche danger in the backcountry...

The Tony Grove and Franklin Basin Roads are not maintained for wheeled travel in the winter.


recent activity

No avalanches were recently reported in the Logan Zone, but conditions were already becoming more active in the mountains above Ogden yesterday afternoon.

Visit our Backcountry Observations Page for more information.....


Avalanche Problem 1
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

Dangerous wind slab avalanche conditions will continue to develop, with increasing west winds and continued heavy snowfall, and are likely to be widespread. Human triggered wind slabs are already likely today in drifted upper elevation terrain, and naturals will become likely as the the storm intensifies and continues later today and tonight.

Avalanche Problem 2
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

The storm snow is piling up on a mix of small near surface facets, surface hoar, and a bit of actual light fresh powder. The snow that was on or near the snow surface in the past few weeks is quite weak, and will likely be a layer that avalanches fail on today. Many avalanche paths now have stating zones that are filled in and smooth, with a hard crust capping the November snow, which could become a good bed surface. Human triggered and natural storm slab avalanches will become increasingly likely with today's windy, wet, and warming storm.


Views of glittery surface hoar or frost on the snow surface. Pretty and perhaps preserved by about an inch of fresh snow now, this could become a persistent weak layer when buried, and accumulating snow is in the forecast. (photos from 12-17-14)

weather

The National Weather Service in Salt Lake City has continue a Winter Storm Warning for the mountains of Northern Utah. West winds are expected to increase further today, while heavy snowfall continues and temperatures increase, causing the elevation of the rain/snow line to rise... It'll rain in the valleys. Snowfall and northwest wind will continue through much of Monday. Should see a bit of a break on Tuesday, but there is potential for a White Christmas in the Valley, with a strong and Cold Pacific Storm late Christmas Eve and Christmas Day.

Check out our one-stop weather page........HERE

general announcements

You can now receive advisories by email for each region in the state including Logan.  Go here for details.

 Get your advisory on your iPhone along with great navigation and rescue tools.......  Utah Avalanche Center mobile app 

Please submit snow and avalanche observations from your ventures in the backcountry HERE. You can call us at 801-524-5304 or email HERE, or include #utavy in your Instagram or Tweet us @UAClogan. To report avalanche activity in the Logan Area or to contact the local avalanche forecaster call me, Toby, at 435-757-7578. 

I'll regularly update this advisory on Monday, Wednesday, Friday, and Saturday mornings by about 7:30.   This advisory is produced by the U.S.D.A. Forest Service, which is solely responsible for its content. It describes only general avalanche conditions and local variations always exist.