Are Above Ground Tornado Shelters Safe Enough?

In many regions, such as parts of Texas and Louisiana, building underground tornado shelters is challenging due to high water tables. In response, some homeowners have opted for above-ground tornado shelters, commonly known as safe rooms. These structures are typically constructed using reinforced concrete and cinder blocks, providing robust protection. However, when it comes to safety during a powerful tornado, these shelters are not as secure as their underground counterparts.

Construction and Durability of Above Ground Shelters

The construction of above ground tornado shelters is usually a combination of reinforced concrete and cinder blocks, designed to withstand severe weather conditions. For example, throwing cinder blocks from a two-story building onto concrete shows that they are resilient; they chip but do not break easily. Additionally, steel-reinforced concrete, when constructed using proper techniques, creates a very sturdy structure. Some hybrid shelters are partially below-ground, offering a mix of protection.

Challenges in Protection Against Tornadoes

The effectiveness of an above-ground tornado shelter depends on its robustness against the high-speed wind vortex, often over 200-300 mph, and the hazards it may contain, such as pointed or sharp items moving at such velocities. In comparison, a wooden wall in a regular house would be easily penetrated by flying objects whipped by strong winds. Therefore, the best tornado shelters are those that are constructed below ground, offering better protection.

Nuclear Bomb Shelters and Their Use for Tornadoes

There is a historical precedent for using sheltered structures in times of danger. During the Cold War, many people built bomb shelters as a precaution against nuclear attacks. These shelters, with reinforced construction, would be suitable for protection against tornadoes as well. If you watched the beginning scenes of Twister or the film adaptation of The Wizard of Oz, the root cellars depicted underground were remarkably safe during violent weather events.

Relative Safety Considerations

While an above-ground shelter may be considered safer than a regular wooden-framed building, it is generally less safe than a properly constructed and drained below-ground shelter of similar materials. Adding a thick earth berm around the shelter can improve its chances of withstanding a strong EF5 tornado.

Conclusion and Recommendations

The safety of above-ground tornado shelters is a relative concept. While they provide significant protection compared to conventional structures, they are not as safe as underground shelters constructed with similar materials. If you are considering purchasing or building a home in tornado-prone areas, it is advisable to include a reinforced basement with a steel safe room. In any case, investing in a properly constructed and fortified below-ground shelter remains the most reliable option to protect against the extreme forces of a powerful tornado.