OK, I've shoveled snow

TWICE now and it's only 11:00 AM. Needless to say we're having a bit of a snow storm, about 10" so far. Does anyone have any ideas how many calories we burn shoveling snow???? It's a driveway (3 car garage) and about 30 feet long (that's a guess, about average length for a suburban neighborhood)
I am not planning on doing my workout today, as I feel like I've already done it, TWICE

and will probably do it again when and if I get home from work.
Let it snow, let it snow, let it snow
Diane