Power may be disrupted or family members may be sleeping during storms, and individuals may not receive the actual warning in time to seek safety. Tornado warnings are usually not issued until a funnel cloud formation is imminent or other phenomena portending funnel formation have been witnessed. Our doors are blast hardened to the same level as our nuclear shelters, in order to protect the entrance from heavy objects that may drop onto the structure. If it is required to mound dirt over the shelter, it should have no more than a 30-degree slope, so that the high winds can 'walk' up and over the mound. We recommend, however, that they have enough cover to keep the interior at a comfortable temperature. Each emergency shelter must have a minimum of two entrances.Īn underground tornado shelter can have a larger diameter entrance with regular staircases, and do not need a deep, 10 ft. Emergency storm shelters can be connected to the commercial power grid, but we discourage any connections to commercial water or sewage systems, as these utilities are at risk for backup and breakage. They also provide good earthquake protection and can function as a safe room, as they conceal easily. Storm shelters can have short side entrances, or even “stove top” emergency exits coming from the ceiling. They do not need the long entrances and 90-degree turns that are required for radiation attenuation in nuclear shelters and are slightly less expensive than the types of emergency shelters that cover 'all hazards'. Underground storm shelters and underground storm cellars are designed for natural disasters, such as tornadoes, hurricanes, winter storms, and earthquakes.

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