Underground shelters, installed below the yard or garage, a pre-built structure designed for in-home placement, and interior rooms like the basement, closet or other room without windows, and ideally located on the first floor or lower, make good shelters during a tornado. Of these structures, underground facilities are generally the safest. They are similar to basements, but have special reinforcing around the ceiling and walls to protect occupants against the strong winds and flying debris from tornadoes, say authors at National Geographic.
Underground tornado shelters are similar to what people see in the movie "The Wizard of Oz," say authors at National Geographic. They consist of a large underground room built below an existing home or in the yard. They are made from sturdy materials like concrete or steel, and seal shut with a heavy door.
Sometimes, terrain and local regulations prevent homeowners from installing an underground shelter. In that case, homeowners can install above-ground, pre-made shelters in their homes, or fortify a windowless room. Pre-made shelters are essentially sturdy cages made of steel; they come in the form of steel cages, as support frames with panels or in a prefabricated design. They are anchored to the house floor, and ideally go in a room in on the first floor.
Homeowners whose homes are under construction can install tornado shelters into their home's framework. Integrated structures are usually made with reinforced materials, such as concrete, steel and wood. They should have no windows, and should be anchored to the home's foundation.