Common route up to the westerly Sunburst ridge – we got to 2,700′ before turning around due to unstable
snow. Hiking required to snow line ~1400′.
Moderate rain in the parking lot, rain/snow line ~1500-1700′, big snow flakes above 2000′. Snowing
2cm/hour (.75″/hour). Very obscured skies and light to moderate northerly winds on the ridge.
Temperature 36F in lot and around 30F at 2,500′
Obvious Signs of Instability:
Recent Avalanches – Wet loose snow sluffs running on a crust and entraining all the new snow were
triggered on a short but steep (40 deg) slope (2,200′ elevation). Unknown activity above treeline – no
Collapsing – No
Cracking – No
1,500-2,500′: 8-12″ of very moist heavy snow from the past 48 hours.
2,500′-2,700′: 12-18″ of moist to dry storm snow. Ski penetration ~15cm
We dug several small pits to look at the buried surface hoar that sits under the storm snow. All pits under
2,500′ showed that the snow was moist/wet enough to penetrate through to the buried surface hoar and
no reactivity was seen – it is sticking well right now. However, triggering a heavy wet sluff is the main
concern at the mid-elevations.
Above 2,500′ where the snow becomes dry – things change. See video below.
Pit @ 2,700′ on West aspect and low slope angle.
ECTP 7 failing 35cm (14″) down on buried surface hoar (3-5mm). Fracture character, Resistant Planar.
Slab was composed of all the new snow in the past 48 hours that is mostly 4Finger hardness with the top
10cm (4″) being Fist hard.
This location was a bit wind scoured – slab depths were increasing further away from ridge.
Below buried surface hoar sat a hard crust from Dec 7-9 rain event.
This is the first persistent weak layer this season in our snowpack. It’s game on and time to pay attention.
Our party did not ascend higher along the ridge due to the instability seen in the pit at 2,700′. Knowing
that the buried surface hoar becomes larger with elevation and snow drier with more wind effect – we did
not venture further.