Quick Answer
Above ground tornado shelters are typically more convenient and accessible, but below ground shelters offer better protection from high winds and flying debris. Below ground shelters are often preferred for larger families and commercial use, but require more excavation and construction effort.
Design and Construction
When it comes to designing and constructing tornado shelters, the main difference between above ground and below ground options lies in their ability to withstand extreme weather conditions. Below ground shelters, also known as underground bunkers, can be built with thicker walls and roofs to provide better protection from flying debris and high winds. In particular, a below ground shelter with a diameter of 8 feet or more and a wall thickness of at least 6 inches can provide a safe space for up to 4 people. Above ground shelters, on the other hand, often require additional reinforcement and anchoring to prevent them from being lifted or overturned by strong winds.
Safety Features and Considerations
Regardless of whether you choose an above ground or below ground shelter, it’s essential to include safety features such as a secure entry and exit system, adequate ventilation, and a reliable escape route. In below ground shelters, it’s also crucial to ensure proper drainage and waterproofing to prevent water accumulation and flooding. In addition, both above ground and below ground shelters should be equipped with essential supplies, such as food, water, first aid kits, and communication devices, to sustain occupants for at least 72 hours. Mobile homes and outdoor structures, which are often not suitable for tornado shelters, should be avoided and occupants should seek alternative safe spaces.
Installation and Maintenance
The installation and maintenance of above ground and below ground tornado shelters differ significantly. Below ground shelters typically require excavation and construction expertise, while above ground shelters can be installed more quickly and easily. Regular maintenance, including inspections and repairs, is essential to ensure the structural integrity and safety of both types of shelters. In particular, above ground shelters may require more frequent inspections to prevent damage from extreme weather conditions and aging materials.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.