|Location:||Lower Eldorado Bowl, Lower Microdot, Lower $1000 Run|
Route & General Observations
Alaska Avalanche School Level 1 Instability Test Day. We split into 3 groups, traveling to Lower Eldorado Bowl, Lower Microdot, and Lower $1000 Run. Touchy, fresh wind slab avalanches triggered on leeward test slopes on lower $1000 run W gully creek side walls and Lower Eldorado NE test slope. Several recent small natural wind slab avalanches noted in cross loaded Eldorado Bowl gullies and Martin Mine gully. Natural small wind slab avalanche noted on N aspect of Wimp Bowl on Peak 4068 and debris visible in SE gully of Marmot.
Obvious signs of instability
|Recent Avalanches?||Yes||Collapsing (Whumphing)?||No||Cracking (Shooting cracks)?||Yes|
Touchy, fresh wind slab avalanches triggered on test slopes on lower $1000 run W gully creek side walls and Lower Eldorado NE test slope. Lower Eldorado Test slope avalanche initiated on ~28 degree slope rolling over into steeper convex slope, and propagated an estimated 100' across and 6" to 16" deep. The wind slab avalanches look to have failed in the new / old interface on a mix of stellar dendrites, decomposing particles, and early near surface facets. Several recent natural small wind slab avalanches noted in cross loaded Eldorado Bowl gullies and Martin Mine gully. Natural small wind slab avalanche noted in N aspect of Wimp Bowl on Peak 4068 and debris visible SE gully of Marmot. Active wind transport at ridgetops during our entire tour from 12:30 to 4 pm at ridgetops from SE winds loading northerly and westerly slopes. Shooting cracks noted in leeward terrain in Lowder Eldorado Bowl test slope area and lower $1000 run.
Overcast to obscured skies. Moderate winds gusting to strong at ~3500'. Temperatures in the mid 20s Farenheit. No precipitation.
Windward slopes (S, SE, E) generally scoured down to old snow or melt freeze crust or still covered by 1" of snow. Leeward (W, N, NE) slopes were wind pillowed in many locations and had wind slabs 2" to 18" thick.
Lower Eldorado Bowl test slope: Any leeward test slopes >25 degrees we tried to investigate to dig on would avalanche or produce shooting cracks. Dug on a NE aspect above the crown of the 100' wide avalanche. Did not see any buried surface hoar, but noted the CNY drizzle crust in some pits. The snowpack was generally right side up with the exception of a thin 2-3" wind slab on top (this slab was much thicker below our pits where it had avalanched). Snowpits tests were unremarkable as there was not enough of a slab to produce propagation or failures in weak layer.
Lower $1000 Run gully sidewalls: Dug pits in W aspect. ECTP2x3, CT1X3, and CTV down 6-8" failing on mix of unconsolidated new snow, partially decomposed snow, or early near surface facets. Wind slabs were more isolated and specific in this area, but very energetic.
No remarkable test results in Lower Microdot.