Why a Violent (EF4-5) Tornado History Matters More Than Frequency

Two different questions, easy to conflate

"How often does a tornado touch this county" and "could a tornado here destroy a code-built house" are different questions with different answers. A high-frequency county with only weak (EF0-1) history and a low-frequency county that took one EF5 are not the same risk, even though the first has the higher touch count.

What EF4-5 actually means for a house

The Enhanced Fujita scale rates a tornado by the damage it did, not a wind gauge reading - EF4 (166-200 mph estimated) and EF5 (over 200 mph) are the two ratings where a well-built, code-compliant house is not expected to remain standing. That is the exact threshold FEMA's P-361 safe-room guidance is built around: below it, a house's structure is the shelter; at or above it, only a separately engineered safe room reliably is.

What this site does about it

Every county page shows the violent-history flag separately from the frequency band, states the exact EF4-5 count, and treats "yes" as the number that should drive the shelter decision regardless of how that county's overall frequency reads. See what a shelter costs for the next step once that question is answered.

Where to go next

See the range this plays out across: Weld County, CO, Oregon County, MO, Kalawao County, HI.

Storm Shelter Cost and State Rebate Programs, in Full · Does Homeowners Insurance Cover Tornado Damage? (It Depends on Your State)