Juneau Area Avalanche Advisory
2006-05-18
Juneau Urban Paths
by Bill Glude, SAAC Observer
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We are now into a cycle of large cornice-triggered wet slab avalanches. On the first warm sunny afternoon of the spring, Saturday the 13th, a large cornice dropped high on the Snowslide Creek path above Thane Road and triggered a deep slab avalanche reached less than 20 m elevation and nearly filled the diversion berm. More recently, a small cornice chunk high on the Snowslide Gulch path up Gold Creek triggered a small shallow slab that in turn ripped out a large deep slab than produced a large avalanche that ran all the way to Gold Creek. Both slabs were big, in the deep 0.5 to 1.5 m thickness range.

Glide cracks remain active and are continuing to produce occasional full-depth glide avalanches, and wet sluffs are widespread.

Backcountry travelers should take care to stay out from under cornices and clear of the slopes below them, stay off of glide plates and their runouts, and expect to trigger wet sluffs on thawing slopes. The avalanche cycles going on now do not generally threaten developed areas, but may do so if a large glide plate releases or a big cornice drops above them.
Photos
Snowslide Creek, Thane Road Path T011, produced this moderately large wet slab avalanche on Saturday afternoon, May 13. The slide ran from the starting zone at 940 m to less than 20 m. We classified it WS-NC-R3D3-O. Saturday was our first really warm, sunny day of the spring following an unusual period of late snowfall at starting zone elevations.
The slab on Snowslide Creek path was clearly triggered by a cornice drop right above the apex of the crown face. We estimated the slab thickness at 0.5 to 1.3 m and the width at 150m.
The debris on the Snowslide Creek path reached less than 20 m elevation, nearly filling the diversion berm for the first time this season. It stopped short of Thane Road.
Snowslide Gulch, Path J007 in Gold Creek, produced its second large late season slab avalanche of the season recently. We just noticed it as the fog broke today, so we believe it fell within the past 24 hours but are not sure. If anyone knows, please let us know so we can post the correct time.

A small section of the lookers' right side of the cornice on the ridgeline broke off, triggering the upper, shallower slab avalanche which in turn released the deeper one in mid-bowl. We estimated the larger crown face at 0.5 to 1.5 m deep and 200 m wide. The slab ran from 950 m to 100 m. We classified it as WS-NC-R3D4-O.
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