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DeKalb County, Illinois

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

Relatively Low overall risk
22nd of 102highest risk in Illinois
$47Mexpected losses a year
10federal declarations
1 in 200homes with flood insurance
Photo: U.S. Geological Survey, public domain

DeKalb County, Illinois has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 81% of US counties. It ranks 22nd of 102 counties in Illinois. The costliest hazards here are inland flooding, cold waves and tornadoes. FEMA estimates about $47 million a year in expected losses, or roughly $472 per resident. Since 1973 it has been included in 10 federal disaster or emergency declarations for natural events (7 major disasters). The most recent was in May 2013 (severe storms, straight-line winds and flooding). Fewer than 1 in 100 homes here carry federal flood insurance (152 policies). Since 1978, federal flood insurance has paid about $4.6 million on 404 claims here, including $1.7 million for floods in 2007.

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

Top risks in DeKalb County

$24.3 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.
$11.6 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.

Tornado

Moderate
$6.9 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.
HazardRatingScoreExpected loss a year
Inland floodingModerate83.0
$24M
Cold waveHigh94.4
$12M
TornadoModerate88.1
$7M
Strong windModerate79.1
$1M
EarthquakeLow75.8
$1M
DroughtModerate74.7
$752K
Heat waveLow59.0
$600K
LightningLow50.1
$253K
HailLow35.1
$158K
Ice stormModerate60.1
$147K
Winter weatherLow32.7
$36K
HurricaneVery Low19.6
$6K
WildfireVery Low6.4
$2K
LandslideVery Low28.7
$304

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 low 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 DeKalb County. 2020s bar runs to November 2026.

By type

Flood3
Snowstorm3
Severe Storm3
Hurricane1

Most recent

May 10, 2013Severe Storms, Straight-Line Winds, and FloodingMajor disaster
Mar 17, 2011Severe Winter Storm and SnowstormMajor disaster
Oct 3, 2008Severe Storms and FloodingMajor disaster
Sep 25, 2007Severe Storms and FloodingMajor disaster
Dec 29, 2006SnowEmergency
Sep 7, 2005Hurricane Katrina EvacuationEmergency
Jul 25, 1996Severe Storms and FloodingMajor disaster
Jan 16, 1979Blizzards & SnowstormsEmergency
Jun 10, 1974Severe Storms & FloodingMajor disaster
Apr 26, 1973Severe Storms & FloodingMajor disaster

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

Storm history since 1957

Tornado risk by county ›

The National Weather Service has logged 495 storm reports in DeKalb County since 1957, with 2 deaths and 31 injuries and about $15.6 million in reported damage. The strongest on record here was an EF3 tornado on April 9, 2015 near Fairdale.

29tornadoes
89hail reports, largest 2.75 inches
322damaging thunderstorm winds
46floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Apr 9, 2015EF3Fairdale11 / 2
Jun 18, 1975F2–1 / 0
Jul 10, 1959F1–0 / 0
Apr 21, 1967F1–0 / 0
Jun 12, 2013EF1Shabbona0 / 0

Most damaging storms

DateTypeNearDamage
Apr 9, 2015TornadoFairdale$8M
Sep 14, 2008Flash FloodFairdale$3M
Aug 23, 2007FloodDe Kalb$1M
Jul 9, 2007Flash FloodDe Kalb$750K
Aug 23, 2007Flash FloodDe Kalb$500K
Aug 23, 2007Flash FloodDe Kalb$500K

Source: NOAA Storm Events Database, county-based reports through Jul 5, 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 DeKalb County

Check your address flood zone ›
0.5%of homes have federal flood insurance (152 policies)
20.5%of homes in mapped high-risk flood zones are insured
$4.6 millionpaid on 404 flood claims since 1978
2007costliest year, with $1.7 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 DeKalb County

$243,600median home value (Illinois $263,300, US $332,700)
1978median year homes were built (Illinois 1971, US 1980)
53%of homes built before 1980, before many modern wind, quake and flood building rules
2.1%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; 41,678 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
Kane CountyHigh14
McHenry CountyModerate14
Winnebago CountyModerate17
Kendall CountyLow11
LaSalle CountyModerate18
Boone CountyLow9
Ogle CountyLow12
Lee CountyLow8

Cities in DeKalb County

Common questions about DeKalb County

What is the biggest natural hazard in DeKalb County?

Inland flooding has the highest expected yearly losses in DeKalb County, about $24.3 million a year in FEMA's estimate. Cold wave is second at $11.6 million.

How many federal disasters has DeKalb County had?

DeKalb County has been included in 10 federal disaster or emergency declarations for natural events since 1973, including 7 major disasters. The most recent was Severe Storms, Straight-Line Winds, and Flooding in May 2013.

Is DeKalb County a high-risk place to live?

Its overall rating is Relatively Low, 22nd 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 DeKalb County?

Standard home insurance does not cover flooding. About 1 in 200 homes in DeKalb 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 DeKalb County had?

NOAA records list 29 tornadoes in DeKalb County since 1950. The strongest was an EF3 tornado on April 9, 2015 near Fairdale. The weather service has also logged 89 hail reports and 46 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.