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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.
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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.

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

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

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EXTREME: Avoid all avalanche terrain.

Advisory Archive - All Zones
Tuesday February 20, 2018 7:30 am by Ethan Davis

Last Seven Days | Last Thirty Days | This Season | All Years | Danger Scale

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

Not The Current Advisory

Sawtooth Mountains - Bottom Line

Triggering a 1-2’ thick slab avalanche remains likely in wind-loaded terrain. Fresh wind slabs have been reluctant to bond to the old snow as evidenced by several natural and a handful of human-triggered avalanches in the last 2 days. Play conservatively today, this problem may take some time to heal.

3. Considerable

Upper Elevation

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

2. Moderate

Middle Elevation

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

1. Low

Lower Elevation

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Smoky & Boulder Mountains - Bottom Line

Triggering a 1-2’ thick slab avalanche remains likely in wind-loaded terrain. Fresh wind slabs have been reluctant to bond to the old snow as evidenced by several natural and a handful of human-triggered avalanches in the last 2 days. Play conservatively today, this problem may take some time to heal.

3. Considerable

Upper Elevation

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

2. Moderate

Middle Elevation

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

1. Low

Lower Elevation

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Wood River Valley - Bottom Line

We will begin issuing danger ratings for this zone if/when access and snow cover improve. Refer to neighboring zone forecasts for general information, especially if you are traveling in the Pioneer Mountains or near the Warm Springs Ck headwaters.

No Rating

Upper Elevation

Watch for signs of unstable snow such as recent avalanches, cracking in the snow, and audible collapsing. Avoid travel on or under similar slopes.

No Rating

Middle Elevation

Watch for signs of unstable snow such as recent avalanches, cracking in the snow, and audible collapsing. Avoid travel on or under similar slopes.

No Rating

Lower Elevation

Watch for signs of unstable snow such as recent avalanches, cracking in the snow, and audible collapsing. Avoid travel on or under similar slopes.

Soldier Mountains - Bottom Line

We will begin issuing danger ratings for this zone if/when access and snow cover improve. Refer to neighboring zone forecasts for general information, especially if you are traveling north of the Soldier Mountains in areas that drain into the South Fork Boise River.

No Rating

Upper Elevation

Watch for signs of unstable snow such as recent avalanches, cracking in the snow, and audible collapsing. Avoid travel on or under similar slopes.

No Rating

Middle Elevation

Watch for signs of unstable snow such as recent avalanches, cracking in the snow, and audible collapsing. Avoid travel on or under similar slopes.

No Rating

Lower Elevation

Watch for signs of unstable snow such as recent avalanches, cracking in the snow, and audible collapsing. Avoid travel on or under similar slopes.

Mountain Weather Summary

A cold, bluebird morning yesterday gave way to increasing clouds mixed with periods of snow and patches of sun. A trace to 1” of low density snow fell in the afternoon and evening before skies cleared overnight. Daytime high temperatures struggled to reach near 10 F while overnight lows plummeted to -10 F. Wind yesterday and last night blew light to moderate from the northwest.

Pack a few extra layers - today will be the coldest day of the week. Despite mostly clear skies, daytime highs will only creep up to near 5 F with light wind from the northwest. Scattered clouds may form this afternoon and should increase to moderate low temperatures overnight. For all of you that prematurely stowed your snow blower and tuned up your mountain bike - shame on you! We’re looking at a few more cold days with light snowfall followed by a promising stormy end to the month of February.

Sawtooth Mountains

Sawtooth Mountains

Last Night
5PM - 5AM

Today
5AM - 5PM

Tonight
5PM - 5AM

Temperature

-9 F 4 F -8 F

Cloud Cover

Decreasing Partly Cloudy Increasing

Ridgetop Wind Speed

Light Light Light

Wind Direction

NW NW W

Snowfall

24hr: 0-1" 12hr: 0-1"
0" 0"

Smoky & Boulder Mountains

Smoky & Boulder Mts

Last Night
5PM - 5AM

Today
5AM - 5PM

Tonight
5PM - 5AM

Temperature

-9 F 4 F -10 F

Cloud Cover

Decreasing Partly Cloudy Increasing

Ridgetop Wind Speed

Light Light Light

Wind Direction

NW NW W

Snowfall

24hr: 0-1" 12hr: 0-1"
0" 0"

Wood River Valley

WRV Mountains

Last Night
5PM - 5AM

Today
5AM - 5PM

Tonight
5PM - 5AM

Temperature

-5 F 4 F -7 F

Cloud Cover

Variable Partly Cloudy Increasing

Ridgetop Wind Speed

Light Light Light

Wind Direction

NW NW W

Snowfall

24hr: 0-1" 12hr: 0-1"
0" 0"

Soldier Mountains

Soldier Mountains

Last Night
5PM - 5AM

Today
5AM - 5PM

Tonight
5PM - 5AM

Temperature

-6 F 0 F -5 F

Cloud Cover

Variable Partly Cloudy Increasing

Ridgetop Wind Speed

Light Light Light

Wind Direction

NW NW W

Snowfall

24hr: 0-1" 12hr: 0-1"
0" 0"

Avalanche Notes

On February 19th a local professional was caught and carried in an avalanche while ski cutting in the western Smoky Mountains. The slab failed about 100 vertical feet below a ridgeline on a NE aspect near 8900' elevation. The slope angle in the starting zone was an estimated 35-40 degrees. The slide broke well above the skier, was 50' wide, approximately 12-18" thick, and ran about 100'. The skier was not buried or injured.

Here’s a quick summary of January snow totals from a few select sites:
Bench: 50”
Lower Titus: 49”
Baldy: 24.5”
Lower Soldier: 33”

On January 16th, an experienced snowmobiler was caught, carried, and partially buried in an avalanche near Dollarhide Mountain. He triggered a 100’ wide, 12-16” thick slab avalanche on a west-facing slope near 8600’ elevation. The slide released about 100’ above him while he was riding on a road. The avalanche carried the rider an estimated 100’ through treed terrain. Fortunately, he was uninjured. We received vague reports of another possible snowmobile-triggered avalanche just north of the Soldier Mountains on the weekend of January 20th-21st.