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| 3.30.2008 |
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This is Chris Lundy of the Sawtooth National Forest Avalanche Center with your Backcountry Avalanche Advisory and Weather Forecast for Sunday, March 30, 2008 at 7:30 am.
The Twin Falls District Bureau of Land Management & the Friends of the Sawtooth Avalanche Center bring you this advisory.
Special Announcement:
Congratulations to Clark Corey who won our Observer of the Year award for submitting no less than 20 observations over the course of the winter. Thanks to everyone who sent in their observations this winter, we can’t tell you how much they help!
This is our last daily advisory of the season. We will issue an update mid week and for the weekend. A special thanks goes to all of our advisory sponsors and to the community who has shown tremendous support for the Avalanche Center and for increasing avalanche awareness in the Wood River Valley.
Bottom Line:
Today the avalanche danger is estimated to be MODERATE. On some easterly and westerly facing slopes, a layer of facets on top of a crust is buried 1-2 feet deep. With this last storm, this layer is now buried deeply enough in the South and Central Valley to be a concern. The distribution and strength of this layer is variable, but it is common enough that these aspects should be carefully evaluated. Due north and south aspects are showing better stability.
Strong winds from two nights ago built sensitive cornices and loaded some upper elevation ridgelines. Continue to use caution on recently wind loaded slopes.
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Primary Avalanche Concern:
A buried facet/crust layer continues to be a concern in our region. It is buried about 2 feet deep in our northern mountains, and in the South and Central Valley it is around a foot deep. It is most common on easterly and some westerly aspects, but its distribution and strength is sporadic. A natural avalanche occurred early yesterday afternoon on Titus Ridge near where skiers triggered a slide on Thursday. From a distance it appeared to be 75-100 feet wide and released mid slope on an east aspect just above 9000 feet. I found this facet/crust layer on a westerly aspect yesterday near Gladiator, but it only produced moderate results during stability tests. Skiers on the Lake Creek/Trail Creek divide in the Central Valley reported this layer as well and received some collapsing.
The variable nature of this layer will require some detective work on your part. If you want to ski or ride on a steep, easterly or westerly facing slope, you’ll need to dig down to see how well the snow is bonded to the underlying crusts. If you see clean and/or easy shears, it would be a good idea to go somewhere else or choose lower slope angles.
Even though many people are thinking spring, as far as our snowpack is concerned, it’s still winter. March spoiled us with conditions that allowed us to go wherever we wanted, but we need to downshift now and realize that recreating in the backcountry requires some stability evaluation and careful terrain selection.
Secondary Avalanche Concern:
I did not see as much wind loading yesterday as I would have expected from Friday night’s wind event, but there were certainly some fresh wind drifts and large, sensitive cornices. Skiers above Trail Creek remotely released a cornice that broke along a 250 foot section of ridgeline. Continue to watch for recently formed wind slabs today and use caution along wind loaded, upper elevation ridgelines.
Current Conditions:
The 6-8 inches of new snow that fell Friday night was surprisingly low density, but the downside is that is was easily moved around by the wind that accompanied the storm. Still, slopes that were sheltered from the wind and sun provided excellent powder conditions yesterday.
High temperatures yesterday reached the teens to mid 20s in the mountains and around 32 degrees in the valley. Ridgeline winds tapered off in the morning and blew lightly most of the day from the northwest. Overnight, winds shifted to the southeast and are currently blowing in the teens. Temperatures this morning are in the single digits at all elevations.
Mountain Weather Forecast:
Skies today should be mostly cloudy in advance of a weak weather system entering our area tonight. This disturbance should only bring a trace to an inch of new snow. Temperatures today should reach the mid teens to 20 degrees in the mountains and the low 30s on the valley floor. Ridgeline winds should average 5-10 mph from a variable but generally southerly direction.
Photos:
1. Beware of Cornices Breaking Back Behind You
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| Reported Conditions |
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| Temperatures |
| Overnight Low |
3 |
9 |
7 |
| 6am Temperature |
3 |
9 |
7 |
| 24 hr Maximum |
12 |
24 |
32 |
| Winds |
| Current Winds |
14 SE |
15 SE |
- |
| 24 hr Average |
9 SW |
11 SW |
- |
| Maximum Gust |
29 WNW |
51 NW |
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| Snow - Storm Interval # 19 |
| Total Depth |
79" |
76" |
40" |
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