Tornado Risk in Hillsborough County, NH
Hillsborough County, NH: what NOAA's tornado record says
20 tornado tracks have crossed Hillsborough County since 1956 by NOAA's count, roughly one every 3.8 years - the Moderate band on this site's scale. That is the 51st percentile nationally for tornado frequency. Among 10 New Hampshire counties in this dataset, Hillsborough County ranks 1 for how often a tornado touches down.
The number that matters more than frequency
No violent (EF4-5) tornado has been recorded in Hillsborough County in NOAA's 76-year database. Of its 20 recorded tracks, 13 were weak (EF0-1) and 7 significant (EF2-3).
Shelter and safe-room economics
New Hampshire does not currently have a confirmed state rebate layered on top of FEMA's 75% Hazard Mitigation cost-share, so a Hillsborough County homeowner should expect the full national range: $2,890-$13,280, $7,645 typical.
Power after the storm, not just shelter during it
A direct hit is not required for Hillsborough County to lose power - outbreak-wide outages across New Hampshire regularly reach homes and businesses well outside the actual tracks. A battery bank covers that gap without a generator's fuel and venting needs.
What Hillsborough County's figure does not tell you
Hillsborough County's figure is county-wide, not address-specific. Hillsborough County covers about 877 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. Hillsborough County has about 430,462 residents.