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| 1.16.2009 |
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This is Janet Kellam of the Sawtooth National Forest Avalanche Center with your Backcountry Avalanche Advisory and Weather Forecast for Friday, January 16, 2009 at 7:30 am.
The Sun Valley Telemark Series & Smiley Creek Lodge & the Friends of the Sawtooth Avalanche Center bring you this advisory.
Special Announcement:
A Rare and Unique Opportunity for Our Community:
“How Does Avalanche Research Help Joe Backcountry?”
Four internationally recognized avalanche researchers are bringing the benefits of their work to the Wood River Valley. Wednesday, January 21st 7-9PM at the NexStage Theater on Main Street, Ketchum. $5.00 at the door.
Bottom Line:
Today the avalanche danger is estimated to be MODERATE. Watch for wet loose slides on steep sunny slopes, especially with daytime heating.
Recently formed wind slabs have gained strength but watch for isolated cracking with the weight of a person, and the possibility triggering of wind slabs and large cornices in high alpine terrain.
Weak layers persist at the base of the snow pack at upper elevations. These have strengthened, but caution is still warranted in steep, rocky terrain on cooler aspects. (Northwest facing slopes through east facing.)
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Danger by Aspect and Elevation:
Primary Avalanche Concern:
A temperature inversion has brought cold overnight temperatures and a good freeze to lower elevations, but mid to upper elevations stayed warmer throughout the night. Upper elevations will warm up more quickly this morning than they did yesterday. Sunny slopes will soften rapidly and surface snow will become wet and loose as the day progresses.
Yesterday, south facing slopes at 9,000ft developed 4 or 5 inches of wet surface snow and we expect this wet layer to become deeper throughout the day. Once the wet snow is deeper than your boot tops, it becomes increasingly possible to trigger wet, loose sluffs that can fan out quite large. Steep, rocky areas on sunny slopes will heat up the fastest.
Secondary Avalanche Concern:
The snowpack is relatively stable and supportive snow conditions have opened up a lot of backcountry, but there are still a few reasons to keep your avalanche antennae out.
Above approximately 8,000ft weak snow still exists at the base of the snowpack on cooler aspects and the possibility of triggering a large avalanche remains a concern in steep, rocky areas with this condition. With warm overnight temperatures and progressively warmer daytime highs forecast for upper elevations, I’d still be cautious about getting on big steep terrain where the weak snow is found.
We are not getting any more reports or observations of sensitive wind slabs, but you should continue to watch for isolated instances in exposed, wind blown terrain where the wind slabs are hollow and drum like. If they sound like a ripe melon when thumped on, this indicates they are sitting on top of weaker snow.
Large cornices have developed from all of our wind storms and loose snow. With today’s warmer temperatures it is a good idea to stay well back from the edges as they can break back further than you might think.
Current Conditions:
A variety of snow surface conditions exists. It is still possible to hunt down some supportive powder on sheltered, north facing slopes. Any open terrain has been hit by wind or sun, and all aspects below approximately 6,700feet have surface crusts. With the right timing, supportive spring-like snow exists on some sunny slopes and in this case, wind packed snow helps create a more solid base.
Baldy’s 6AM temperature is reporting 40 degrees. We think this thermometer is reading a bit warm but never-the-less, temperatures began rising around midnight, have taken a brief drop at sunrise and currently are at or above freezing at 9 to 10,000ft. Ketchum is reporting 12 degrees and Stanley minus 2. Winds are light out of the north and northwest. Yesterday in most locations the temperatures climbed into the mid to upper thirties, Baldy reporting a high of 44 degrees.
Mountain Weather Forecast:
Today with only light winds forecast, expect temperatures to warm rapidly at upper elevations. It may reach forty degrees on Titus Ridge and will certainly rise into the mid forties on Baldy. Lower elevations will remain in the cool temperature inversion until mid day, but it should get close to 40 degrees on the valley floor. Morning fog will linger in the lowest valleys and in Stanley.
Temperatures should cool down overnight but will remain inverted with warmer conditions at upper elevations. It looks like this pattern will persist through the weekend and into next week as a blocking, high pressure continues to build over the western US.
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| Reported Conditions |
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| Temperatures |
| Note: Inverted. |
| Overnight Low |
27 |
34 |
12 |
| 6am Temperature |
31 |
40 |
12 |
| 24 hr Maximum |
35 |
44 |
38 |
| Hours Below Freezing |
7 |
0 |
14 |
| Winds |
| Current Winds |
14NW |
7NW |
- |
| 24 hr Average |
13NW |
7NW |
- |
| Maximum Gust |
23N |
15NW |
- |
| Snow - Storm Interval # 11 |
| Total Depth |
45" |
37" |
22" |
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Announcements:
The Avalanche Beacon Park is up & running on Sun Valley Road next to the Catholic Church. All you need is a beacon and probe as well as snowshoes or skis to get around in the snow. It is free and has easy instructions posted on it. We've moved a few of the targets around in the past few days.
Your observations are invaluable - they help us produce more accurate advisories which in turn helps you. If you get into the backcountry, let us know what you see out there - especially if you see or trigger any avalanches. Call (208)622-0099 or fill out the observer form on our web site. http://www.sawtoothavalanche.com/submit_observation.php
The south-facing slopes above Warm Springs Road have been closed for winter elk habitat from the West Fork of Warm Springs to Wanderer's Way. Please avoid all wintering game animals throughout the valley; it is getting very difficult for them with the increasing snow depths.
Check http://www.wrh.noaa.gov/pih/ for the latest weather forecasts.
For Idaho road closures and openings check: http://511.idaho.gov/
For a recording of this advisory, call the Avalanche Hotline - (208)622-8027.
This information only applies to the backcountry and does not apply to highway programs or operating ski areas. Changing conditions and local variations may occur.
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