Steamboat & Flat Tops
AvalancheBrian Gardel, Max Strotbeck · Dec 31, 2022 · Steamboat & Flat Tops
Weather
Skies were Obscured and snowing all day. Snowfall rates ranged 1-2"/hr. Winds were Light to Moderate BTL and Moderate gusting Strong out of the W and NW at ridgeline (NTL). Temperatures NTL were in the low to mid-twenties.
Snowpack
Total snow depth ranged 150-300cm depending on aspect and elevation. We found the deepest snowpack NTL on east-facing leeward slopes near the Soda ridgeline. Avg snow depth was 200cm. Storm total from Dec 28-31 is approx. 36", with last night's storm snow coming in upside down combined with some wind. Overall the mid and lower pack is rounding and gaining strength. Our biggest concerns were surface instability and potential to initiate the stubborn Xmas Eve ice crust now buried 65-80cm down. Surface snow was quite touchy. We noted lots of localized cracking and were able to easily trigger small test slopes. Extended column test results: Lower Bonzai Trees (9300', N, HS 180cm): ECTP1 @ 15cm failing in the storm snow on a density change interface. ECTP30+ @ 72cm failing above the Xmas Eve ice crust. Soda (10,700', N, HS 210cm): ECTP1 @ 15cm Soda - top of Ebut (10,600', N): ECTP1 @ 16cm Soda - top of Funnel (10,600', SE, HS 300cm): ECTP1 @ 50cm x2 failing in the new snow, and ECTP30+ @ 90cm. Ice crust was 110cm down.
Avalanche
One small natural avalanche (SS-N-R1-D1-S) on steep north facing terrain in the Bitch Creek failed 15cm from the surface in the new snow. One small avalanche (SS-U-R1-D1-S) on steep north facing terrain in the Dad's road cut failed 15cm from the surface in the new snow. Either natural or snowcat triggered? We intentionally triggered a small avalanche on a steep N facing chute near "The Ramp" of Soda (SS-ASc-D1), again failing 15cm down within a density change in the new snow.