CNN Heroes: To the rescue - finding a purpose for rejected shelter dogs

Santa Paula, California (CNN) - When disaster strikes and people are buried in rubble, there's often no better search tool than a dog's nose.
It's a valuable asset that has already been utilized several times this year. Trained search dogs, along with their human handlers, have provided help in high-profile disasters such as the Japan earthquake in March and the Joplin, Missouri, tornado in May.

"After a disaster, there is a window of opportunity for finding live people," said Wilma Melville, founder of the National Disaster Search Dog Foundation. "The first eight hours are critical."

There are about 250 search-and-rescue teams, each made up of a dog and a handler, that are certified by the Federal Emergency Management Agency. But Melville says that's half as many as there should be.

Read more about Wilma here.