Community programs such as maintaining a volunteer system of weather spotters may increase rates of local tornado detection and improve warning dissemination. Because of the strong association between the strength of tornadoes and their potential to cause death or serious injury, tornado-related disaster preparedness should concentrate on those parts of the country that have high numbers of violent tornadoes (Fujita classes F4 and F5). Another important component of disaster preparedness is to educate the public to seek appropriate shelter, particularly in public buildings such as schools. Improved hazardous weather awareness can also be promoted by encouraging households located in tornado-prone parts of the country to have National Oceanic and Atmospheric Administration (NOAA) "Weather Radios," which provide 24-hour information to the public concerning adverse weather conditions.