Tornado Risk in Sully County, SD
How likely is a tornado in Sully County, SD?
22 tornado tracks have crossed Sully County since 1965 by NOAA's count, roughly one every 3.5 years - the Moderate band on this site's scale. That is the 53rd percentile nationally for tornado frequency. Within South Dakota alone, Sully County ranks 49 of 66 counties for tornado frequency.
The number that matters more than frequency
No violent (EF4-5) tornado has been recorded in Sully County in NOAA's 76-year database. Of its 22 recorded tracks, 21 were weak (EF0-1) and 1 significant (EF2-3).
Shelter and safe-room economics
South Dakota does not currently have a confirmed state rebate layered on top of FEMA's 75% Hazard Mitigation cost-share, so a Sully County homeowner should expect the full national range: $2,890-$13,280, $7,645 typical.
Power after the storm, not just shelter during it
1,468 people live in Sully County, and a tornado outbreak's power loss usually reaches far more of South Dakota than the tracks themselves touch. A portable battery unit is the faster, no-fuel way to bridge that outage.
What Sully County's figure does not tell you
Sully County's figure is county-wide, not address-specific. Sully County covers about 1,007 square miles, so a single touch here counts the same as a single touch in a county a fraction of that size. NOAA also documents that older records undercount weaker tornadoes from before Doppler radar became standard. Sully County has about 1,468 residents.