By Lucy Alexander — For some homebuyers, the fantasy of coastal living will forever outweigh the risks. But rising sea levels and shifting sands can mean getting closer to the ocean than you might have intended.

By Polly Mosendz and Eric Roston — If you happened to be in Montauk, N.Y., when the trucks started rolling in this summer, you’d get a sense of how much sand $171,000 buys.