Safety is of primary concern during a big storm or tornado, which is an immensely powerful, destructive force that can devastate anything in its path. Historically we have been told to move into a cellar or basement but an above ground shelter is a much better solution, especially for the elderly or disabled that find it difficult or impossible to climb down the steep, narrow stairs of traditional underground shelters in an emergency situation when every second counts! It is important to have a safe place to go during a storm, such as an Action Concrete & Fence above ground storm shelter.
The wind speeds at the ground level have not been decisively measured, and the estimates given by Doppler radar are for 500 feet above the ground. At ground level, there are obstructions, which can affect the wind velocity, limiting it in areas and funneling into higher velocities in others. Typically, tornado strengths are measured, not by Doppler wind speeds above ground, but by the damage assessment on the ground, making the measurement of the strength of the tornado a subjective rather than objective matter.
Most underground shelters have only one entrance/exit. Their door opens upward to prevent debris falling in and injuring or further trapping the occupants while they are trying to exit, but this can pose a serious problem if, for instance in a garage, collapsed building materials are sitting on top of the door. The occupants would be trapped until someone could remove this material. This may pose an additional risk, especially for those with health problems.
Storm shelters built above ground also avoid other issues that can plague underground shelters. An above ground shelter has a door that opens outward, which is supported by a secured locking point in the door frame. There is a much lower chance of debris falling in and trapping someone in an above ground shelter, and with the door opening inward, it is not necessary to wait for rescuers to exit after the storm. Localized flooding can be a problem in any storm, and those that spawn tornadoes or super-cells, are also prone to produce heavy rainfall. Below ground shelters are more prone to take on water, and without a clear drain system, can fill up.