Snow covering roof vents - an issue?
So I've read a LOT recently about attic venting and the science of proper eve/soffit vs roof vents, insulation types and quantities, vapor barriers, baffles in vaulted ceilings to ensure air flow, vented vs unvented approaches, etc, etc. But one really basic question I can't seem to find an answer to is... when snow covers roof vents, wouldn't that render them more or less useless? It's not uncommon in many parts of the country (mine included) to get 1-2 feet of snow, which is more than enough to entomb vents such as ridge or turtle vents.
Is there something obvious I'm missing here?