| Recent Avalanches? | Yes |
| Collapsing (Whumphing)? | Yes |
| Cracking (Shooting cracks)? | No |
Observation: Turnagain
Location: Sunburst
Sunburst – one lap to 3500′ via standard uptrack and down a SW aspect, then up via Taylor Pass to 3500′, descending on a W aspect
Obvious signs of instability
Observer Comments
Observed a very small natural dry loose avalanche in action on a westerly aspect, apparently triggered by some moderate wind transport; several other D1 dry loose slides could be seen on the south aspect at upper elevations. Some wet loose avalanche activity was seen on Sunnyside from the day or days prior, as it was present this AM, with some additional activity by mid-afternoon. Pictures of both are below.
One fairly far reaching collapse around 2500' on the flats between Sunburst and Magnum, with two people noting it ~100' apart.
Weather
Few clouds in the AM increasing to broken skies, then overcast - but with shadows present - late in the afternoon.
Winds in the AM were light, increasing above treeline throughout the day to moderate gusting strong from the NE.
Light to occasional moderate snow transport at ridgeline late in the afternoon.
Temps below freezing, but solar radiation made it feel warm!
Snow surface
Dry snowpack - a major change from yesterday! - at all elevations and all aspects in the AM. When we left at 4 PM, 1-2" of moist snow on solar facing, steep rollovers below 2000'. Parking lot flats remained dry at 4 PM.
Road -> 1200' - light dusting of snow on a supportable 5cm melt freeze crust over 4-6" of fist hard weekend storm snow
1200' -> 1800' - 1-2" of soft snow on a semi supportable 3cm melt freeze crust, over 6-18" of fist -> 4 finger weekend snow
1800' -> 2400' on the uptrack - 1-2" of soft snow over a thin breakable crust. Ski pole probing revealed a ight side up snowpack down to a firm layer ~60cm from the surface.
Surface formation on the standard uptrack above 2400'.
Above 2400' - some spatial variation due to weekend winds, with ground exposed on Magnum's north aspect and even some mid elevation ridges on Sunburst's southwest face, but generally soft, right side up snow with ski penetration of 3-6". Very minor skier induced sluffing on steeper slopes.
3-6mm surface hoar along the standard uptrack above 2500'
Snowpack
Dug one pit just NW of Taylor Pass, in a slightly wind loaded location well below ridgeline
3000', W aspect, 30 degree slope, Height of Snow = 255cm
(Probing leading up to the pit location revealed HS generally between 200-220cm)
Weekend storm snow was 85cm deep, right side up from fist -> 1f plus over a 5 cm layer of 4f+ facets.
CT22, 25 RP down 40cm in a mid storm density change, but no failure at the new/old snow interface. ECTX.
Final Note: We skied this location last weekend, and compared to other places, I think this site had a thicker weak layer and a less firm bed surface when compared to other parts of Sunburst.
Spoke to another party that dug just east of the entrance to Elevator Shaft on the Sunburst ridgeline - they reported ECTP15, but with low energy, with 2-3' of snow from the weekend storm.
Surface hoar on Sunburst, and a view of Magnum's north aspect
Previous wet loose activity along sunny side referenced above
Natural dry loose avalanche that we saw in action as referenced above, just off the Sunburst ridgeline