X
Avalanche Danger Rose: this graphic represents an avalanche forecaster's idea of how the avalanche danger exists across the topography in a given region. It is not a map...it is an idea. Picture it as a cone-shaped mountain viewed from above, built of three elevation bands; the outer ring represents low elevations, the middle ring represents middle elevations, and the innermost circle represents high elevations. Each elevation band is divided into sectors that represent the slope aspect (N-NE-E-SE-S-SW-W-NW). Each sector\'s color represents the avalanche danger rating assigned that day (see Avalanche Danger Scale).

In this example, the Avalanche Danger Rose depicts an avalanche danger rating of considerable on all high elevation aspects and on north to west-facing mid elevations; all other sectors possess moderate avalanche danger. The illustration depicts the spatial distribution of this forecast across a landscape.
X Wind Slabs: A relatively cohesive layer that forms when wind deposits snow on the lee side of ridges, gullies, and other terrain features. These slabs may be soft or extremely hard and can take up to a week to stabilize.
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X
Avalanche Problem Rose: this graphic represents an avalanche forecaster's idea of the distribution of a particular avalanche problem across the topography in a given region. Picture it as a cone-shaped mountain viewed from above, built of three elevation bands; the outer ring represents low elevations, the middle ring represents middle elevations, and the innermost circle represents high elevations. Each elevation band is divided into sectors that represent the slope aspect (N-NE-E-SE-S-SW-W-NW). Sectors colored grey are thought to have the identified avalanche problem while white sectors do not.

In this example, the Avalanche Problem Rose indicates that a particular avalanche concern exists on all high elevation aspects and on north to west-facing mid elevations and that this concern is far less likely to be encountered on other aspects and elevations.
X Chance of Avalanches: This graphic depicts how likely you are to trigger avalanches or encounter natural avalanches while traveling on avalanche prone slopes. Unlikely means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. The chance of triggering or observing avalanches increases as we move up the scale. Certain means that humans will be able to trigger avalanches on many slopes, and natural avalanches should be expected.
X Size of Avalanches: This graphic depicts the potential size and destructive force of expected avalanches. Small avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become large enough to bury, injure, or kill people, large enough to bury or destroy vehicles and break a few trees, and large enough to destroy railway cars, buildings, or a substantial amount of forest. Historic avalanches are massive events capable of destroying villages and gouging or altering the landscape.
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LOW: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

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MODERATE: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

X

CONSIDERABLE: Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

X

HIGH: Very dangerous avalanche conditions. Travel in avalanche terrain is not recommended.

X

EXTREME: Avoid all avalanche terrain.

Current Advisory
January 16, 2017 7:30 am by Ethan Davis

All Zones | Sawtooth Mountains | Smoky & Boulder Mountains | Wood River Valley | Soldier Mountains

Sawtooth Mountains

Bottom Line: The avalanche danger is MODERATE at upper and middle elevations. Today you may encounter thin, fresh wind slab formed yesterday afternoon. Beneath it lies thicker, stiffer wind slab that formed last week. You’re most likely to trigger an avalanche involving these slabs on steep wind-loaded slopes at upper elevations. The danger is LOW at low elevations - unstable snow may exist in isolated wind-affected terrain.

Special Announcement

Hey snowmobilers and snowbikers, have you heard about the Motorized Level 1 avalanche class the Friends are hosting in Fairfield next weekend? We still have some spots open so email us at info@sawtoothavalanche.com for more information or to sign up.

Primary Avalanche Problem

Wind Slabs   

Aspect/Elevation   

Certain
Unlikely

Chance of Avalanches   

Historic
Small

Size of Avalanches   

The last four days have been generally calm and warm. Stability is continuing to improve in many areas as time separates us from loading due to snow and wind. Yesterday, observers in the alpine along Titus Ridge reported good stability but increasing winds as the afternoon wore on. Sun Valley Heli Ski observed blowing snow off the highest peaks in the Smokys and SAC staff observed it first hand near Galena Peak in the Boulder Mountains (photo). By the end of his tour Ben observed isolated cracking and thin, sensitive wind slab formation. Wind data from Upper Vienna showed moderate north and northeast wind, and similar conditions are possible in the high alpine of the Sawtooths. Any fresh wind slab may be touchy as it forms slabs over a mix of facets, crusts or old wind slab. If you encounter similar conditions, make conservative decisions and plan cautious climbing and descent routes to avoid steep slopes.

Today, it will be possible to trigger smaller, sensitive wind slabs or larger more stubborn wind slabs that have formed since our last storm. It may seem obvious but it’s worth reinforcing that you're most likely to trigger these slides in heavily wind-affected terrain. Generally speaking, wind speeds increase with higher elevation and less trees to provide shelter. Wind deposits form below ridges and in cross-loaded mid slope depressions and gullies. As I head out, i’ll be anticipating terrain features that may harbor wind slab (new or old) and seek out softer snow to ride.

Additional Discussion:
Last weeks storm was a doozy, dropping anywhere from 3-6’ of snow. So far, most observations have found no obvious weak layers and point to a good bond at the new and old snow interface. This is good news, but there are some interesting outliers. Yesterday, I investigated a large slide in the Smokys on a steep, upper-elevation southeast aspect. The slide failed at the base of our storm snow in a weak faceted layer beneath a crust. Additionally, cracking and collapsing was observed Friday near Trail Creek (Wood River Valley) where some south-facing slopes have shown a weaker bond to the old-snow surface. It’s not clear what the distribution of this weaker interface is, but it may take longer to heal. Today, no matter your aspect, look for stronger snow (slab) over weaker snow near the surface. Dig down beneath our recent snow and check for this crust or weak sugary facets. If these layers exist, how well they are bonding? It’s important to do this same detective work in rocky areas where you may impact lingering instabilities near the ground.

Weather Forecast

Last Night
5PM - 5AM

Today
5AM - 5PM

Tonight
5PM - 5AM

Temperature

10 F 25 F 12 F

Cloud Cover

Clear Clear Clear

Ridgetop Wind Speed

Moderate Light Light

Wind Direction

NE N NW

Snowfall

24hr: 0" 12hr: 0"
0" 0"

Avalanche Notes

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Mountain Weather Summary

Yesterday was another beautiful day in paradise. High temperatures reached into the mid-20s F, the sun bathed the snow and light wind blew from the west and north. By the afternoon hours moderate northwest wind ramped up in portions of the high alpine and blowing snow was reported on Galena Peak. Overnight, light to moderate wind continued from the northwest and mountain temperatures dipped into the teens. Impressive temperature inversions have set up once again this morning as it’s near -20 F in the Stanley Basin and Fairfield, and hovering around zero in the Wood River Valley.

High-pressure dominates our big picture weather through Tuesday deflecting moisture to our north. Today’s weather will be very similar to yesterday. Daytime highs will edge into the mid-20s F and light wind will blow from the north as we enjoy another sunny day. Expect increasing clouds Tuesday and a shift back to a more active weather pattern by Wednesday.

Sawtooth Mountains

Last Night
5PM - 5AM

Today
5AM - 5PM

Tonight
5PM - 5AM

Temperature

10 F 25 F 12 F

Cloud Cover

Clear Clear Clear

Ridgetop Wind Speed

Moderate Light Light

Wind Direction

NE N NW

Snowfall

24hr: 0" 12hr: 0"
0" 0"

Smoky & Boulder Mountains

Last Night
5PM - 5AM

Today
5AM - 5PM

Tonight
5PM - 5AM

Temperature

16 F 25 F 12 F

Cloud Cover

Clear Clear Clear

Ridgetop Wind Speed

Light Light Light

Wind Direction

W N N

Snowfall

24hr: 0" 12hr: 0"
0" 0"
           

Wood River Valley

Last Night
5PM - 5AM

Today
5AM - 5PM

Tonight
5PM - 5AM

Temperature

19 F 24 F 13 F

Cloud Cover

Clear Clear Clear

Ridgetop Wind Speed

Light Light Light

Wind Direction

N N NW

Snowfall

24hr: 0" 12hr: 0"
0" 0"
   

Soldier Mountains

Last Night
5PM - 5AM

Today
5AM - 5PM

Tonight
5PM - 5AM

Temperature

17 F 26 F 16 F

Cloud Cover

Clear Clear Clear

Ridgetop Wind Speed

Light Light Light

Wind Direction

W NW N

Snowfall

24hr: 0" 12hr: 0"
0" 0"
           

General Information