It's made more likely that they (when there's first an overlap in their shooting) would select the same picture by virtue of getting roughly the same shots and their shots being likely to have many of the same qualities. Chances are they'll value many of the same qualities and so would at least exclude shots of many of the same moments for the same reasons.

That they're professional photographers might reduce the odds by virtue of there being fewer of them, but might increase the odds by virtue of them being more likely to be the kind of people to know of specific spots to go out of their way to take pictures from during a storm, and more likely to value the same qualities i their shots, as well as more likely to publicize their photos enough for one of them to find the other persons photo.