Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Thursday - January 19, 2017 - 7:01am
bottom line

Heightened avalanche conditions exist in drifted terrain, and triggered wind slab avalanches are possible. Evaluate the snow and terrain carefully. Avoid steep slopes with deposits of wind-drifted snow, ridge-top cornices, as they could break back further than expected, and steep, rocky slopes with thin overall snow cover.




current conditions

The Tony Grove Snotel at 8400' reports 25 degrees F with 87 inches of total snow containing 160% of average SWE (Snow Water Equivalent). It's 17 degrees F at the CSI Logan Peak weather station at 9700', with a 30 mph south-southeast wind, gusting to 53 mph early this morning. We're hoping winds will destroy much of the widespread surface hoar before it's buried and preserved by light snow today. But, this is probably just wishful thinking, and the surface hoar is likely to be a buried persistent weak layer in some areas after today's light snow.


Surface hoar is widespread in the Logan Zone.
recent activity

No new avalanches have been reported since last week's widespread, natural avalanche cycle.

List of notable activity from last week:

  • A natural avalanche hit Hwy 89 in the Beaver Canyon section of Logan Canyon just after noon Wednesday, closing the road until Thursday morning.
  • A dirt-filled natural avalanche in Zanavoo Gully in lower Logan Canyon ran about 2800' early Thursday morning, stopping 100 vertical feet above the Logan River Trail.
  • Natural avalanche activity in the Wellsville Range was extensive, and HUGE fresh natural avalanches can be seen from across Cache Valley.
  • Observers reported large, natural avalanches from the recent cycle on the east face of Mt. Magog, Cornice Ridge, Providence Peak, Hell's Kitchen, Tab Hollow, Steam Mill, Wood Camp, and Thurston Hollow in the Mount Naomi Wilderness.

Large, natural avalanches from last week in the Wellsville Range above Mendon.
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

Increasing south wind last night created a heightened danger of wind slab avalanches in exposed upper elevation terrain.

  • Drifts likely formed on weak surface snow consisting of surface hoar and/or small-grained sugary faceted snow, and fresh wind slabs could be quite sensitive today.
  • Wind slabs made up of stiffer drifted snow are often rounded and chalky and may produce hollow, drum-like sounds.
  • Avoid drifted snow on the lee side of ridges and in and around terrain features like gullies, scoops, sub-ridges, and cliff-bands.
  • Cornices could break further back than expected and may trigger wind slab avalanches on drifted slopes below.
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

Persistent slab avalanches, failing on buried weak layers, are unlikely but possible. Large, natural avalanches stepping into old snow were common during last week's storm. Weak layers of faceted snow exist above and below rain-crusts at mid and lower elevations. The snow is weakest in rocky terrain where it's thin or shallow. These types of avalanches are low probability - high consequence, meaning you're unlikely to trigger one, but if you get caught, you could get killed or seriously injured.

weather

An active pattern will develop across the region, with a series of weather systems crossing the area through the middle of next week. A high temperature of 29 degrees is expected at 8500', with moderate southwest winds and 1 to 3 inches of snow. It should drop to 18 degrees F tonight, with moderate northwest wind and 1 to 3 inches of snow expected. There's a 50 % chance of snow tomorrow, with moderate northwest wind and a high temperature at 8500' of 29 F.
general announcements

Any time is a great time to practice companion rescue techniques with your partners. Companion Rescue Practice Video

The National Avalanche Center just released their Avalanche Problems Explained video... Not all avalanches are made the same. As a result, travel and decisions in avalanche terrain are influenced by the kind of avalanche you expect to encounter. Watch HERE

Discount lift tickets for Beaver Mountain, Snowbasin, Powder Mountain, and the Central Wasatch resorts are donated by the resorts to benefit the Utah Avalanche Center. Details and order information here.

Your information can save lives. If you see anything we should know please help us out by submitting snow and avalanche observations. You can call us at 801-524-5304, email by clicking HERE, or include @utavy in your Instagram. In the Logan Area you can reach me at 435-757-7578

We will update this advisory regularly on Monday, Wednesday, Friday, and Saturday mornings by about 7:30.

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 exist.