Avalanche Advisory
Advisory: Ogden Area Mountains Issued by Evelyn Lees for Monday - January 22, 2018 - 7:19am
bottom line

The Avalanche Danger is MODERATE on steep, mid and upper elevation slopes facing northerly through easterly. Human triggered avalanches are possible, and large, dangerous avalanches can be triggered in isolated places. Use a slope inclinometer and compass to identify and avoid the steep, north through easterly facing slopes, where it’s most likely to trigger an avalanche.

Today’s increasing southwesterly winds will also create a MODERATE danger for triggering wind drifts along ridge lines.

Low angle slopes of all aspects have superb turning and riding in classic Utah powder.
special announcement

Episode 3 of the UAC podcast went live last night. We talk with UDOT Avalanche Program Supervisor Bill Nalli on how he and his teams keep the Greatest Snow on Earth from avalanching over the open roads and highways of the state. Find it on our blog site (linked above), iTunes, Stitcher, or wherever you get your podcasts.

Do you know the parable of the Scorpion and the Frog? A short piece of fiction from Mineral Fork here.
current conditions

It’s going to be another powder preserving day, with increasing clouds, cold temperatures and light winds. Under mostly clear skies, temperatures in the Ogden area mountains are in the teens this morning, with single digits on the highest ridge lines. Winds are from the southwest, averaging less than 5 mph at the low and mid elevations. The higher ridge lines and peaks have wind speeds of 15 to 20 mph, with gusts to 25 mph at the moment.

The weekend storm delivered - storm totals of around 15” of superb, low-density powder, greatly improving conditions. Cloudy skies and cold temperatures yesterday kept the snow soft on all aspects.
recent activity
  • In the Ogden area mountains, 2 skiers were caught in an avalanche at Snowbasin. A serious slide, but the outcome was good - though one person was buried, they were recovered quickly and OK. The second person also took a ride, but ended up on top with only minor injuries.
  • reports of some new activity on Ben Lomond - shallow, new storm snow avalanches along the higher ridge line.

Doug Wewer photo, Ben Lomond

Mike Fogg photo, Monte Cristo, one of the weak facet layers clearly visible

All recent Ogden observations HERE.
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

The unpredictable, multiple layers of buried faceted snow are a serious problem – they were the weak layer of at least 5 human triggered slides in northern Utah over the weekend - two yesterday and 3 on Saturday - and are the likely culprit of the two weekend fatalities in the west.

Slides in Utah are averaging 2 to 3 feet deep, and over 100 feet wide. The layers of weak, sugary facets they are failing on are notoriously tricky, and the snowpack’s response to the weight of a person is erratic and variable. But the location of the slides are not random – the have been triggered on steep, shady slopes facing northwest through easterly, at the mid and upper elevations, and avoiding those slopes is the best way to avoid triggering an avalanche in the backcountry. Avalanches can still be triggered remotely and from below.

With the weekend refill of perfect powder, lower angle slopes of all aspects once again have excellent riding and turning conditions.
Avalanche Problem 2
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 12 hours
description

There are enormous amounts of snow available for transport, and even wind speeds as low as 15 mph quickly move low density snow into drifts. Along the ridge lines, snow will be moving today and forming soft drifts. These can be triggered on steep slopes, and will be most widespread on north through easterly facing slopes. The drifts should be mostly confined to right along the ridge lines, but look for drifts anywhere you find the wind blowing
Avalanche Problem 3
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

ast moving sluffs can be triggered on steep slopes of all aspects, far running where they are on slick underlying sun and wind crusts, entraining all the storm snow in the path below. They tend to break below a person, though can be serious if they pile up deeply in a gully or terrain trap.
weather

As a weak disturbance scoots by to the north, there will be increasing clouds today and a chance for a few snowflakes near the Idaho border. Temperatures will try to crawl out of the icebox, warming into the upper teens to upper 20s. The southwesterly winds will average less than 10 mph at most low and mid elevations, but speeds will increase with elevation. Average speeds of 15 to 25 mph, with gusts to 40, are possible along the high ridge lines by afternoon. Temperatures and wind speeds will increase tomorrow ahead of a fast moving storm, which should bring a shot of snow Thursday night.
general announcements

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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.