Recovery efforts after natural disasters are always difficult. But the mudslide that wiped out the community of Oso, Washington, last month, killing at least 29 people with 20 still missing two weeks later, has left behind such hellacious conditions that recovery workers are stymied at every turn. And so are their dogs.

With experienced sniffer dogs on the ground, officials hoped to quickly account for the rest of the missing. But "while dogs can be a great asset, they aren't miracle workers," says Marcia Koenig of King County Search Dogs, a handler of search-and-rescue canines for the last 42 years. We spoke to her about why this disaster site presents problems she's never before encountered and why even the