I have to agree with Mike and with the moderator of owlpages.com; large owls do just fine busting through deep snow and even ice layers when hunting mice. (Ive written a published paper on this subject.)

But Mike is incorrect in referring to Great-horned Owls with the implicit assumption that their catholic diet is similer at Barred Owls; it is not. Barred owls, like Great Gray Owls, primarily eat small mammals in the north country in winter. This winter, and every winter when the mouse populations are low, Barred Owls are forced (by hunger) to hunt more during the day and to visit feeders and roadsides where rodents are more abundant and/or easier to find. Barred owls are ARE FOOD STRESSED in the Adirondacks this winter. This is the second winter in a row with no cone crop, an unusual event in recent decades in the Adirondacks as the climate warms (cone crops typically have been a binannual event in the past 2-3 decades). Mouse (and conifer-seed eating finch and nuthatch) populations are severely depressed in the Adirondacks compared to when there is a conifer seed crop (as there will undoubtedly be this coming winter).

So, I agree with Brian except that I think the snow pack has nothing to do with Barred Owls appearing more along roadsides, and thus being more prone to vehicle collisions.