How Likely Is a Tornado in Lyman County, SD?
Lyman County's tornado history, by the numbers
Lyman County has recorded 43 tornado touches in NOAA's 76-year database, a rate of roughly one every 1.8 years - our High band. Put another way: Lyman County sees more tornado activity than 82% of US counties. South Dakota has 66 counties in this dataset; Lyman County ranks 14 of them by frequency.
Beyond the frequency band: violent history
37 weak and 5 significant tornadoes make up Lyman County's 43-track record - none violent. NOAA has never logged an EF4 or EF5 crossing this county.
The dollar figure Lyman County's rating leads to
Cost nationally: $2,890-$13,280, about $7,645 typical. South Dakota has no state rebate program confirmed here; FEMA's underlying 75% cost-share exists nationwide, but applying through a state program is what usually makes it real, and none was found for South Dakota this pass.
What a direct hit isn't required for
Power loss after a tornado outbreak in South Dakota often reaches homes the storm itself never touched. A battery-backup unit covers the outage without the fuel and venting a generator needs.
What this number is, and is not
One caveat before relying on Lyman County's number: it is county-wide, and it covers about 1,642 square miles, so a single touch counts the same as one in a county a fraction of that size. Weaker pre-1990s tornadoes are also documented as undercounted in NOAA's own record. Lyman County has about 3,721 residents.