Observation Date: 12/27/2019

Southern Missions 4300’  to 7000′

20º-22º f throughout day
Snowing all day, 1″-3″ in 5hours depending on elevation

Light wind with moderate gusts.
High winds at alpine ridgetops evident at times.

New Snow: 6-12″

Avalanche Activity:
Sluffing, loose snow releasing easily and sliding fast.
No other signs of instability.

Other Comments:
The southern Mission’s  have the deepest snowpack I’ve seen this year.
105cm (41″) at 5700′ and 160cm(63″) at 6800″
Pits at both elevations revealed a much more consolidated snowpack than in other areas.
Lower snowpack is mostly pencil to finger hardness.
Some faceting remains in the lower snowpack, although it is rounding. there is good bonding happening around the crusts.
The structure is improving, but still has a way to go. The depth will help it round out.

Tests showed:
-High strength
-Low propagation propensity
-Medium friction (energy)

Test results:
5700′ east aspect, HS 105cm (41″) 31º slope
CT1 SP (Q1), down 16cm (6″) in near-surface facets below melt-freeze crust.
PST 75/100 end, down 77cm (30″) in softest facet layer

6800′ north aspect, HS 160cm, 21º slope
CT21 RP (Q2), down 45cm (18″) on near-surface facets
CT24 BRK (Q3), down 130cm (51″)
PST 95/100 end, down 90cm (35″) in rounded facets above crust

All aspects below 6200′ and southern aspects above 6200′ have a melt-freeze crust sitting on 5cm of near-surface facets, with up to 20cm (8″) new snow on top. There is likely surface hoar on top of the crust in some areas based on the previous few nights weather, although we were unable to find any.

Compression tests showed low strength and low friction on the near-surface facets under the crust. It is not currently an issue due to the shallow depth and light unconsolidated snow on top but will likely become a problem layer with further loading and consolidation. A good thing to note and be aware of as we get more snow.

Riding was good, especially on higher elevation (<6200′) North slopes. The crust is getting buried and lower elevation riding 5500-6200′ is improving. Below 5500′ still needs considerable snow to cover hazards and a stout crust.

Observer: Jeff Carty