Logan Avalanche Advisory

Forecaster: Toby Weed

BOTTOM LINE

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


Danger Rose Tutorial

There are areas with a level 2 or Moderate danger in the backcountry around Logan, and heightened avalanche conditions exist on some steep drifted slopes. You could trigger wind slab avalanches, mainly at upper elevations and in exposed, lee terrain. Although fairly unlikely, more dangerous hard slab avalanches running on buried persistent weak layers are still possible in isolated places with significant deposits of recently drifted snow. Solar warming will cause a possibility of wet avalanches on slopes with damp or saturated surface snow. Despite these exceptions, the danger is Level 1 or Low and the snow appears stable on most slopes in the zone. Continue to practice safe travel protocols and evaluate the snow and terrain carefully, especially on recently drifted of sun softened slopes...

CURRENT CONDITIONS

Mountain temperatures are around 10 degrees warmer this morning than yesterday's, and it looks like it'll be a very nice day in the backcountry. You'll find nice shallow powder riding conditions, with dust-on-crust in some areas, and a solid and supportable base in most areas. The Tony Grove Snotel at 8400' reports 24 degrees and 92 inches of total snow on the ground, containing a bit over140% of normal water content for the date.

RECENT ACTIVITY

We triggered an audible collapse or whumpf near the Big Baldy ridge-line yesterday, and we also instigated a bit of cracking and released a couple small wind slabs that didn't go anywhere in First Waterfall Hollow above the quarry in Providence Canyon. Another party reports triggering a couple small soft and manageable wind slab avalanches in the Tony Grove Area on Thursday. Monday afternoon, we proved that avalanches running on persistent buried weak layers are possible when we remote triggered a fairly large hard slab avalanche from around 40 feet away on our way down the lower Steam Mill/White Pine ridge. There were also a handful of natural wind slab avalanches observed earlier in the week.

Check our backcountry avalanche list.... HERE

THREAT #1
WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Some of the stiff wind slabs that built earlier in the week are resting on weak sugary snow and/or feathery surface hoar above a solid ice-crust from mid-January rain. Soft or stiffer wind slab avalanches are possible on some previously drifted slopes steeper than about 35 degrees... Dangerous and destructive hard slab avalanches involving old snow, running on January weak layers below the ice-crust, and in the 1 to 3 foot-deep range are unlikely but still possible on isolated slopes with significant recent wind loading and existing buried weak layers. Other than the presence of recently drifted snow, there may be no prior warning signs, but remember that collapsing is a major red flag. You might trigger a persistent slab avalanche remotely or from a distance, and hopefully not from below....

THREAT #2
WHERE PROBABILITY SIZE TREND
      Over the next 24 hours.

Watch for and avoid wind drifts on steep slopes off the lee sides of ridges and sub-ridges, under cliff bands, around rock outcroppings, along gully walls, or in scoops or depressions. Cracking in the surface snow is a red flag. Ridgetop cornices could break further back and be larger than expected, and falling cornice chunks might trigger wind slab avalanches on slopes below. Increasing southwest winds this weekend will probably cause a more widespread danger of fresh wind slab avalanches in exposed terrain.

THREAT #3
WHERE PROBABILITY SIZE TREND
      Over the next 10 hours.

With mountain temperatures climbing well above freezing today, many sunny slopes may be adversely affected by the higher angled February sun, and wet avalanches are possible on any slope where the fresh surface snow becomes damp or saturated. This is most likely to occur on sunny and sheltered mid and lower elevation slopes today, and shallow fresh snow will probably mean fairly low involved wet snow volumes.....

MOUNTAIN WEATHER

We'll see a good deal of sunshine in the mountains today and through the weekend, with a high pressure firmly in place over the area. Mountain temperatures will warm up a bit today with a high of about 35 degrees forecast for 8000', and moderate and increasing southwest winds. South and southwest winds will intensify overnight and will be fairly strong tomorrow, with gusts of around 40 mph possible. We'll see a slight chance of a little snow Monday night, but probably just a few more clouds as a mild southwest flow developes. Models agree upon a shift in the overall weather pattern, with a deep through and stormy conditions to move over our area on around Thursday. There are disagreements around timing of storm features, but it looks pretty good for some regular old Utah powder conditions in the later half of February.

GENERAL ANNOUNCEMENTS

You can view a photo summary of last year's avalanche activity in the Logan Area HERE

Join the friends of the Utah Avalanche Center in Logan on facebook. Click HERE

I will update this advisory in the mornings on Mondays, Wednesdays, Fridays, and Saturdays, and on other days if backcountry avalanche conditions warrant...

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 Toby at 435-757-7578, or email by clicking HERE

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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 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.