Well it’s that time of year. The WSDOT has announced that they are starting the yearly challenge of clearing off Highway 20. Last year I predicted the pass would be clear on April 5th and the actual date was April 3. Nailed. It. OK, now I’ve jinxed this year.
I’ve added last years data to the prediction. Here is the chart. 
Using the depth on 3/1/2016 of 39 inches from snotel this means my prediction for this year is April 12 (there is some carefulness about leap year that I am ignoring.)
Actual was 4/22