There have been some reports that underground storm shelters, or safe rooms, in Moore, Oklahoma, did not hold up during yesterday's massive tornado that devastated the community.

Many of course did withstand the storm, including one that we know saved a man, his wife and their children.

Megyn Kelly discussed the basics of storm shelters, which are effectively small bunkers where a family can huddle with some basic supplies until a tornado passes. The door on top is supposed to be able to withstand the tornado's tremendous winds. She went over the main issues with Dr. Irwin Redlener of the National Center for Disaster Preparedness and Ric Rhodd, VP of Hausner Inc, the largest provider of storm shelters in Oklahoma.

The local school superintendent told Megyn earlier in the show that the district cannot afford the cost of putting storm shelters in its schools. Rhodd said it costs anywhere from $2,500-$4,000 in the Moore area for a home storm shelter.

Rhodd said that he is not aware of any specific cases of shelters failing to hold up yesterday, but he noted that the age of the shelter is a factor, in addition to whether the homeowner did the required maintenance on the unit. Rhodd said in recent years, municipalities have set up databases to keep track of which homes have shelters, so emergency responders know where to go after a tornado hits.

If you don't have a shelter or a basement and a tornado is on its way, Redlener said you should find a place inside your home away from windows and hold on to whatever might be the most stable, even a toilet. He said if you do have a storm shelter, you should keep a whistle of some kind in it so you can alert authorities to your location.