Avalanche Advisory
Advisory: Ogden Area Mountains Issued by Drew Hardesty for Thursday - February 23, 2017 - 7:03am
bottom line

The danger is CONSIDERABLE today for soft wind drifts and all-but-certain long running sluffs in the low density snow. These will be big enough to catch, carry, and bury a person today. The danger may spike to HIGH during periods of high snowfall rates or if the winds become unreasonable and gusty. Remember that avalanche terrain includes runout zones beneath steep terrain.

HOT TIP! - Low density snow is still world class on low angle slopes.




current conditions

It's like the days of old. Temps are in the teens and upper single digits. Winds are westerly, blowing 15-20mph in exposed locations.

Overnight and storm totals (snow/snow-water-equivalent) are 6"/0.6" and varying from 13"/1.18" to 18"/2.0".

Snow conditions are world class.
recent activity

Yesterday's activity included skier and explosive triggered sluffs and shallow soft slabs up to a foot deep, with some running on the 2/20 crust. In the central Wasatch, two cornice fall events triggered hard slab avalanches 3' deep, perhaps running on the 2/10 crust.

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

Sensitive, long running point release sluffs will run both naturally and with provocation on steep slopes of all aspects today. Sluffs, as opposed to slab avalanches, start at a point and fan out, gaining momentum while entraining more loose snow while cascading down the slope. They tend to require steeper slope angles to run (approaching 40° and steeper). Today's sluffs will be big enough to catch and carry a person and bury them in the deposition zone below.

*These will run naturally today during periods of higher snowfall intensity. Avoid being in runout zones where naturals or human-triggered slides can engulf you.

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

The westerly winds spiked to 15-20mph with gusts to 30-40mph for a few hours around dinner time last night. These wind slabs are now buried under a few inches of fluff and may still be triggered on steep north to east to south facing slopes in typically wind exposed terrain. Current Ogden skyline wind speeds of 25-35mph are easily enough to drift the low density snow in the high exposed terrain. Watch for shooting cracks on steep slopes.

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

The ever growing cornices will continue to be a significant concern for those traveling along or underneath ridgelines today. It would be a mistake to encroach onto the larger, more concealed cornices to drop a new soft cornice. As shown, these significant triggers may be enough to pull out storm snow down to the February 10th rain crust, resulting in a more dangerous avalanche.

weather

A cold, unstable west to northwest flow will keep off and on snow showers throughout the day. Watch for periods of higher snowfall rates or occasionally gusty west winds above 10,000'. Temps will continue dropping toward 0°F along the high ridges. It's likely we'll pick up another 6-12" through tonight with snow showers likely tomorrow as well. Another weak storm on tap for later Saturday and another one later Sunday into early week.

general announcements

Remember your information can save lives. If you see anything we should know about, please help us out by submitting snow and avalanche conditions. You can also call us at 801-524-5304, email by clicking HERE, or include #utavy in your tweet or Instagram.

To get help in an emergency (to request a rescue) in the Wasatch, call 911. Be prepared to give your GPS coordinates or the run name. Dispatchers have a copy of the Wasatch Backcountry Ski map.

Backcountry Emergencies. It outlines your step-by-step method in the event of a winter backcountry incident.

If you trigger an avalanche in the backcountry, but no one is hurt and you do not need assistance, please notify the nearest ski area dispatch to avoid a needless response by rescue teams. Thanks.

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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