As asphalt shingles age, the ends can start to curl and they get brittle. So when a strong wind blows one backwards, well, you may find yourself with a torn shingle tab—the cause for a lot of roof leaks.
To replace the damaged shingle, you have to first separate it from those above and below it with a flat bar. Then pry up the nails to completely remove it.
Now you’re ready to put a new shingle back in its place. You’ll need to nail it down using two nails in the top half of each tab and then add a little roofing cement on top of each nail. This will correct the problem for now, but it doesn’t mean your troubles are over.
If this shingle was brittle enough to break, chances are there are several more in the same condition, and a new roof is likely in your not too distant future.