We recently had a windstorm move through our area of Washington (yeah,
we're all over the news) that deposited about 20-30 of my asphalt
shingles all over my backyard. I looked at the roof carefully, and
there's no plywood showing, the places where shingles came off still
have shingles underneath, there were and are no leaks. Is it
necessary to have these replaced immediately, or is it even necessary
at all? If I need to replace them eventually, how does one go about
replacing individual shingles?