We saw your tracks heading out this morning. By the looks of your accomodations, I understand your early departure now. We were surprised by the plentiful snowfall last night. We were camped half way down the lake and had a 4am wake-up call to try the NE Couloir on Colchuck, which turned to a 6am revised plan just to ski the Colchuck glacier.
I'd say your estimate of 15 cm at 2:30am is probably right and it was still whiteout and snowing at 8:30am when we abandoned the plan due to no visibility. Enough snow had fallen that we barely hit the crust on the ski down. Interestingly, it doesn't appear to have appreciably snowed anywhere else in Washington State last night.