Technically, we're several tens of miles east of Tornado Alley, but as I noted in my first comment, the accepted standard for residential and commercial buildin

Technically, we're several tens of miles east of Tornado Alley, but as I noted in my first comment, the accepted standard for residential and commercial building out here is 90 mph, which will handle more than 50% of all tornadoes (https://en.wikipedia.org/wiki/Enhanced_Fujita_scale https://en.wikipedia.org/wiki/Enhanced_Fujita_scale). And the odds of any particular location getting hit with any sort of tornado are small; in fact, I gather that derechos (https://en.wikipedia.org/wiki/Derecho https://en.wikipedia.org/wiki/Derecho) do more, but much less intense, damage since they effect vastly larger areas of land. It's just not worth the resources to build everything to handle > EF0 tornadoes, better to have alerting systems for people to listen to them and get to safety in time, although of course safety in an EF4/5 tornado is not trivial. We had 20 minutes of warning before it touched down, with 2 warnings sounded, and it took 5 minutes to make its way to my location. A large fraction of the fatalities were from people who simply didn't heed the warnings.