Caribou Creek (Flattop)

We traveled in the Caribou Creek drainage to gain observations on new snow slab formation building over weaker interfaces. As expected, we observed  isolated cracking while traveling and easy propagating results in snowpack tests on weak interfaces buried 1 to 3 feet deep. The snowpack will remain sensitive as it adjusts to the recent heavy loading from new snow and winds.

At 4000 feet we observed 45cm snowpack height with 15cm of soft new snow sitting on top of a hard but decomposing crust. Snow depths increase to 70cm at 5200 feet with marginal coverage of logging slash in clear cut areas. At this elevation, we observed a wind pillowed location with 140cm snowpack height produce two mod to hard force propagating results: ECTP 14 and 22, down 60cm (Grinch crust) and 70cm respectively from the surface. Both these results were on top of rain crusts. 

Further up at 6050 feet on a sheltered north aspect we observed easy propagation down 30cm (1ft) (ECTP 5, twice). At this interface down 30cm, we could not find buried surface hoar but believe this is the 1/1 interface with 4F hard snow above and F hard snow at this interface. No other instability test results were observed at this location but a weak structure of crusts with difficult to detect hardness changes (less differing hardness than expected) near these crusts.

Main crusts we found present at this location:

• Very Thin, 2mm thick, rime crust down 25cm. 
• Grinch crust (P hard, 0.5 thick, down 35cm), 
• P- hard, 5cm thick, decomposing sandwich of crusts down 45cm
• Knife hard 1cm thick crust down 52cm with 4F small faceted grains above crust.