Such a weird story.
Over a dozen human feet (usually still in the shoe) have washed ashore over the last few years on British Columbia beaches. Now at least 1 has been identified. The consensus is that they were once attached to people who have been killed in the areas many nearby rivers/bays, the foot detached once the body rotted enough and the buoyant sneaker helped it be carried to the beach.
Click the source link(s) for more.
2010 -> http://nyp.st/cGGBTQ
Source -> http://abcnews.go.com/blogs/headlines/2011/10/feet-that-washed-ashore-identified-as-missing-canadian-woman/