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Stephenson County, Illinois

Natural disaster risk, federal disaster history and flood insurance facts.

Relatively Low overall risk
30th of 102highest risk in Illinois
$29Mexpected losses a year
12federal declarations
1 in 333homes with flood insurance
Photo: U.S. Geological Survey, public domain

Stephenson County, Illinois has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 74% of US counties. It ranks 30th of 102 counties in Illinois. The costliest hazards here are inland flooding, tornadoes and cold waves. FEMA estimates about $29 million a year in expected losses, or roughly $648 per resident. Since 1969 it has been included in 12 federal disaster or emergency declarations for natural events (8 major disasters). The most recent was in September 2019 (severe storms and flooding). Only 48 homes here carry federal flood insurance. Since 1978, federal flood insurance has paid about $3.6 million on 193 claims here, including $1.5 million for floods in 2017.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in Stephenson County

$15.8 million a yearExpected losses. Damaging events about once a year.
  • Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
  • Price a flood policy now. Most new federal policies take 30 days to start.

Tornado

Moderate
$3.9 million a yearExpected losses. Damaging events about once every 2 years.
  • Pick a shelter spot: a basement, or an inside room on the lowest floor with no windows.
  • Turn on emergency alerts on your phone and keep a weather radio.

Cold wave

Moderate
$3.4 million a yearExpected losses. Damaging events about 6 times a year.
  • Insulate pipes in outside walls, crawl spaces and garages.
  • Know how to shut off the main water valve.
HazardRatingScoreExpected loss a year
Inland floodingModerate77.9
$16M
TornadoModerate82.3
$4M
Cold waveModerate80.8
$3M
HailModerate93.3
$2M
Strong windHigh85.1
$1M
DroughtModerate81.0
$878K
Heat waveLow63.7
$610K
EarthquakeVery Low57.7
$360K
Ice stormModerate69.7
$191K
LightningLow47.2
$187K
Winter weatherLow44.3
$47K
WildfireVery Low27.0
$11K
HurricaneVery Low15.1
$3K
LandslideVery Low52.3
$1K

Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is relatively moderate and community resilience is relatively high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

Federal declarations for natural events that included Stephenson County. 2020s bar runs to November 2026.

By type

Flood4
Snowstorm4
Severe Storm3
Hurricane1

Most recent

Sep 19, 2019Severe Storms and FloodingMajor disaster
Mar 17, 2011Severe Winter Storm and SnowstormMajor disaster
Aug 19, 2010Severe Storms and FloodingMajor disaster
Mar 13, 2008Record Snow and Near Record SnowEmergency
Aug 30, 2007Severe Storms and FloodingMajor disaster
Dec 29, 2006SnowEmergency
Sep 7, 2005Hurricane Katrina EvacuationEmergency
Jul 25, 1996Severe Storms and FloodingMajor disaster
Jul 9, 1993Severe Storms & FloodingMajor disaster
Jan 16, 1979Blizzards & SnowstormsEmergency
Show all 12
Jun 10, 1974Severe Storms & FloodingMajor disaster
Aug 30, 1969Heavy Rains & FloodingMajor disaster

Illinois also had 2 statewide declarations that did not name single counties.

Storm history since 1956

Tornado risk by county ›

The National Weather Service has logged 514 storm reports in Stephenson County since 1956, with 2 deaths and 4 injuries and about $18.3 million in reported damage. The strongest on record here was an F2 tornado on October 8, 1958.

23tornadoes
136hail reports, largest 3 inches
265damaging thunderstorm winds
54floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Oct 8, 1958F2–0 / 0
Apr 17, 2026EF2Lena0 / 0
Jun 1, 1971F1–0 / 0
Aug 24, 1998F1Pearl City0 / 0
Apr 17, 1959F1–0 / 0

Most damaging storms

DateTypeNearDamage
Jul 22, 2017FloodWinslow$8M
Jul 5, 2003Thunderstorm WindCountywide$3M
Oct 8, 1958Tornado–$3M
Apr 19, 1996Thunderstorm WindPearl City$1M
Jul 22, 2010Flash FloodWaddams Grove$1M
Jul 27, 2011Flash FloodWaddams Grove$500K

Source: NOAA Storm Events Database, county-based reports through Jul 3, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.

Flood insurance in Stephenson County

Check your address flood zone ›
0.3%of homes have federal flood insurance (48 policies)
9.4%of homes in mapped high-risk flood zones are insured
$3.6 millionpaid on 193 flood claims since 1978
2017costliest year, with $1.5 million paid

National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.

Homes in Stephenson County

$134,900median home value (Illinois $263,300, US $332,700)
1960median year homes were built (Illinois 1971, US 1980)
75%of homes built before 1980, before many modern wind, quake and flood building rules
3.6%of homes are mobile homes, which are the least safe in tornadoes and high winds

Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 21,330 housing units.

Compare in Illinois

All 102 ›
Largest countiesOverall riskTop hazard
Cook CountyVery HighInland flooding
DuPage CountyHighInland flooding
Lake CountyHighInland flooding
Will CountyHighInland flooding
Kane CountyHighInland flooding
McHenry CountyModerateInland flooding
Winnebago CountyModerateInland flooding
Madison CountyModerateInland flooding

Neighboring counties

CountyOverall riskDeclarations
Winnebago CountyModerate17
Ogle CountyLow12
Green County, WILow15
Jo Daviess CountyLow14
Lafayette County, WIVery Low12
Carroll CountyVery Low14

Common questions about Stephenson County

What is the biggest natural hazard in Stephenson County?

Inland flooding has the highest expected yearly losses in Stephenson County, about $15.8 million a year in FEMA's estimate. Tornado is second at $3.9 million.

How many federal disasters has Stephenson County had?

Stephenson County has been included in 12 federal disaster or emergency declarations for natural events since 1969, including 8 major disasters. The most recent was Severe Storms and Flooding in September 2019.

Is Stephenson County a high-risk place to live?

Its overall rating is Relatively Low, 30th highest of 102 in Illinois. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.

Do I need flood insurance in Stephenson County?

Standard home insurance does not cover flooding. About 1 in 333 homes in Stephenson County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.

How many tornadoes has Stephenson County had?

NOAA records list 23 tornadoes in Stephenson County since 1950. The strongest was an F2 tornado on October 8, 1958. The weather service has also logged 136 hail reports and 54 floods here.

Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.