From obs: "Noticed this large avalanche in unsupported terrain yesterday morning. I called it HS-N-R3-D3-U although it looks to have failed on facets at the ground. Frequent flyer but impressive. Debris was approx. the size of a football field and 8-10' deep, ran full extent of D3 track." A Newman
Noticed this large avalanche in unsupported terrain yesterday morning. I called it HS-N-R3-D3-U although it looks to have failed on facets at the ground. Frequent flyer but impressive. Debris was approx. the size of a football field and 8-10' deep, ran full extent of D3 track.
We dug on a nearby slope. 8050', E/SE, 29 deg. HS 200cm, N/O interface down 40cm. 1cm MFcr with small grained facets above and below. Fair structure, no prop. A bit of grapple mixed in new snow and todays solar input was not warm enough to soften current surf. crust
From IG message 3/11/23: "...yesterday, at Fairy Lake, very windy and this slid naturally sometime between when we got to the area at noon and 3oclock. There was also a smaller natural wind slab in the northern bowl with arrowhead. Observed wind loading all day."
From IG message 3/11/23: "...yesterday, at Fairy Lake, very windy and this slid naturally sometime between when we got to the area at noon and 3oclock. There was also a smaller natural wind slab in the northern bowl with arrowhead. Observed wind loading all day."
From IG message 3/11/23: "...yesterday, at Fairy Lake, very windy and this slid naturally sometime between when we got to the area at noon and 3oclock. There was also a smaller natural wind slab in the northern bowl with arrowhead. Observed wind loading all day." Photo: P. Norvell
As we were leaving the zone, loose snow naturally flushed out of the steep north /east facing couloirs / cliffs NW of Ainger Lake, fell over some cliffs, and triggered additional dry loose and what appeared to be some small storm slab pockets, out onto the apron.
Viz was not great re: details, but it was a humbling amount of snow moving on its own, without any obvious signs of warming or wind transport. No other yellow flags observed throughout the tour.
We skinned up the east face of the Throne and dug at the top of the east face (8100 ft, east aspect) and again on the north facing slope at top of the throne itself (8300 ft, north aspect). Snow depth of ~7 ft on the east face and ~4 on the north. ECTX in both pits. No cracking, collapsing, or other signs of instability. No avalanches observed. Little wind effect in the new snow. South aspects starting to get a surface crust, no crust on east or north.
