Whether it was from the Arbor Day Tornado Outbreak or any damage video you've seen from other major tornadoes, one theme becomes apparent: tornado damage can vary wildly between buildings. One home could be wiped off the face of the Earth, while its neighbor feet away only has minor damage. It may sometimes feel that tornadoes uniquely have it out for people, but is there any explanation for it?
There is, in fact, and the reasons can be broken down into three broader categories.
1. TORNADIC WINDS
Tornadoes are complex and ever-evolving. Winds within a tornado are not uniform throughout its path or within the tornado. For example, over the 33-mile span of the Elkhorn-Bennington-Blair EF-4 tornado, there were only four instances of EF-4 damage during its path: three homes in Elkhorn and one in Washington County. The rest of the path saw mostly EF-1 to EF-3 strength winds.
Then, there's the winds inside the tornado. Tornadoes often have vortices, or small vortexes of higher winds relative to the rest of the tornado. These can be random and move within the tornado. This is where the small-scale details come into play. Let's say your home gets hit with a 150 mph vortex, but your neighbor is missing so only sees 100 mph winds, this will change the damage structure within the tornado.
2. HOME CONSTRUCTION
Alongside tornadic winds, home construction is a major factor in the type of damage. When a home was built, what materials were used to construct the home, how it is anchored to the foundation, whether it uses certain wind-resistant materials, and more all play major factors into home damage during tornadoes.
Many homes also have failure modes that can increase the chances of them being destroyed. Attached garage doors and large bay windows are both big failure modes that allow winds to get inside the house, making it easier to be damaged.
3. OTHER RANDOM FACTORS
Outside winds and home construction, a final factor is a hodge podge of other random factors. A few examples of these are:
- Debris hitting the home, weakening it
- The way the home is facing when the tornado hits
- Local geography (i.e., home is sitting on a hill or valley)
- Surroundings (lots of trees or other homes to knock into it)
- and more
Regardless of how well your home is constructed, when a tornado warning is issued for your region, take those tornado precautions.
