Juneau Area Avalanche Advisory
2006-02-19 to 20
Fish Creek Knob
by Bill Glude, SAAC Observer
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Text
We taught a Level I avalanche course in Juneau over the 3-day weekend. We worked on Mt. Troy on Saturday, and used Fish Creek Knob for our field area on Sunday and Monday. Weather was good, with a little sunshine on Saturday, and light fresh snow with mild but subfreezing temperatures, good visibility, and light winds on the other two days. The snow was a bit crusty but not all bad, with softer spots on shaded aspects where the breakable suncrust did not form last week.

The snowpack has settled over the last mild week. All our tests had very strong results except on the recent sun and rime crusts over faceted snow near the surface. Those weak layers do not yet have much load, and do not show up prominently in our testing because they are still too close to the surface, but they are likely to be quite sensitive if they are rapidly loaded.

In the meantime, the major instability is from riders catching edges in the sun and rime crusts.
Field Notes
Photos
We try to make learning fun in our Level I courses. Here, Emily Ferry tags off as Andy Altenburg and Kai Ottesen sprint for the tagging tree in the observations relay race.
Amber Bethe of Skagway and Angela Coleman of Ketchikan are in a near-tie as they reach for the tagging tree.
Kristen Dunlap stretches valiantly for the tagging tree as Nick Waldo reaches from the backside.
Angela Coleman and Kristen Dunlap take notes on their test pit results.
The block tests produced uniformly strong results this weekend, prompting this innovative flying-leap jump test by Kristen Dunlap and Nick Waldo. To see the results, click the link for a 4-photo sequence made into a QuickTime movie.
Nick Waldo does a tap compression test, tapping with increasing force from the wrist , elbow, and shoulder on a shovel blade on a 30 x 30 cm column sawn out from the snowpack while watching carefully for shear or collapse fracture.
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