I recieved a call on Monday, January 17th about a possible skier/snowboarder
triggered avalanche in the south fork of Timber Creek . After another call to the
source of the information I decided to go investigate on a bluebird Thursday.
Carson Baughman and Dan Morris from the Forest Service were also interested in
checking it out so we met at the FS offices at 7:30 AM and headed over to Timber
Creek on the west side of the Schell Creek Range. When I picked Carson up at his
home he had a spotting scope focused on the east side of the Egan range above
Steptoe Valley. We were able to spot new avalanche crowns on almost every N by
NE slope on the Egans. It is safe to assume that these were natural slides.
The slope in question in Timber Creek is a North by North East facing slope that I
have seen release snow slides naturally at least once a winter in the 6 winters I have
been back-country skiing in these mountains. It is virtually clear of trees because of
this and it is directly above the summer trail into the South Fork of Timber Creek. The
top of the slope has a small rock band just above a 40 degree roll over. During heavy
snow storms the snow builds up on the rocks but then releases onto the slope often
triggering the natural slides.
The starting zone was on this 40 degree slope just below the band of rocks on a
convexity in the slope. The elevation is 10,000 feet at the top and 9,300 feet at the
main deposition zone at the bottom. It ran down to a bench above the trail and a
portion of the debris ran down to the creek below it another 100 feet or so. This was
not the largest avalanche I have seen on this slope but it did pack a punch and was
the first time that it was probably skier triggered.
The snow depth at the starting zone was 90 centimeters, the bed surface of the initial
fracture was 50 cm's down on a 5 cm bridging layer, there was 20 cm's of faceted hoar
and another small bridging layer below that just above the ground. The slide stepped
down to this layer within 50 feet below the starting zone. Off to the sides of the slide
path the slide did not step down to this layer.
The last snow that fell before this slide was on the 12th of the month and there had
been a significant warming trend in air temperatures starting on the 15th.
Climbing the slide path we could see the tracks of a snowboard descending. We
could see the ski tracks enter the slope at the starting zone but we saw no sign of the
ski tracks on the slide path going down.
There were tracks of two people walking out of the deposition snow and there was a
spot where someone had dug down in the debris in the deposition zone.
We are going to put a request in the local paper for the folk involved to contact us with
their first-hand account.
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