Parking garages are multi-story concrete structures designed for vehicle storage, not severe weather shelter. Determining their safety during a tornado depends on the specific structural design and the storm’s intensity. While these structures possess inherent strengths, their open-air nature introduces unique vulnerabilities to tornadic winds. The perception of a concrete monolith offering absolute protection does not fully account for the dynamics of a high-speed rotating wind event.
Structural Design and Tornado Resistance
Parking garages are designed with significant structural strength to handle the sustained vertical loads of hundreds of vehicles. The core framework utilizes heavy, reinforced concrete and structural steel, materials inherently more resistant to wind forces than standard wood-frame buildings. This mass provides resilience against the high wind speeds associated with lower-intensity tornadoes.
A deep foundation system anchors the structure, designed to resist uplift forces caused by wind. Thick concrete slabs and beams create a rigid, box-like structure that performs well against lateral wind loads. These components are engineered to maintain integrity, giving the buildings a perceived safety advantage.
Unique Hazards of Open-Air Structures
Above-ground parking garages possess critical vulnerabilities due to their lack of fully enclosed exterior walls. The large, open sides act as funnels, allowing high-velocity debris to enter the structure unimpeded on every level. This debris, including signs, road materials, or vehicle parts, becomes a dangerous projectile hazard across the entire floor plate.
The multi-story design can create a wind tunnel effect if the wind aligns with the structure’s long axis. This acceleration of air pressure increases stress on supporting columns and the potential for internal damage. Garages rely heavily on perimeter columns, unlike fully enclosed buildings that use interior shear walls to distribute wind loads.
If an EF-2 intensity tornado or higher strikes, the failure of a few perimeter columns from debris impact or wind loading can initiate a progressive collapse. The lack of internal load-bearing walls means that if a floor section loses support, the weight of the cars and concrete above can cause multiple levels to pancake downward. This structural weak point is why above-ground garages are not considered safe shelters during a severe tornado event.
Immediate Safety Protocols and Shelter Alternatives
Parking garages are not a substitute for a purpose-built storm shelter. The safest alternatives include underground parking levels of adjacent buildings, dedicated basements, or the innermost, windowless hallways and stairwells of large, reinforced commercial structures. These locations offer multiple layers of concrete and steel between occupants and the storm’s forces.
If an above-ground parking garage is the only option during a tornado warning, move immediately to the lowest level possible. Seek shelter near the structure’s most reinforced cores, such as elevator shafts or stairwells, which typically contain thicker concrete shear walls. These areas offer the best protection from wind-driven debris and the risk of structural collapse.
Position yourself away from any openings, entrances, or ramps, as these are the paths for the highest wind speeds and debris ingress. If no reinforced core is accessible, getting under the sturdiest vehicle available may offer a final resort shield against falling debris. The goal is to maximize the amount of concrete structure between you and the outside elements while minimizing exposure to the open sides.