[jyl]

Hmm. I arbitrarily chose two feet.

Digging into it a bit more (ha ha), I see that all-time record snowfall in Portland was 61 inches in the winter of 1892-1893 - that's cumulative for the whole season, not snow accumulation at any given time. In the past century, there was 19 inches of snowfall during the winter of 1919-1920. In 1968-1969, there was up to 10 inches of snow accumulation. In 1950 33 inches fell during the month of January with "over a foot" of snow accumulation on the ground. Recent years' snowfall has been much milder. 12 inches during 2003-2004, 21 inches in 2008-2009 - but again that is over the whole winter, in 2008-2009 at my location we had at most 8 inches accumulation, but it was wet stuff.

So maybe my "two feet of wet snow" is excessive. Or maybe I should simply assume that, should it happen, my plastic panels will break, and I'll simply replace them. Or that I'll remove the accumulation - when it snows in Portland, I work from home.