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Stephenson County, Illinois severe weather history spans 518 recorded events between 1956 and 2026. The dominant hazard is thunderstorm wind, accounting for 50.4% of all recorded events. It ranks #813 nationally and #27 in Illinois.
518
Recorded events
0
Direct deaths
4
Direct injuries
$17.6M
Property damage
The record
What the Stephenson County, Illinois severe weather history record shows
Across the archive, Stephenson County, Illinois severe weather history averages 7.4 recorded events a year. The busiest stretch on record is the 2000s, with 170 events logged in that decade alone. Roughly 50 events fall before 1990 and 468 from 1990 onward — a gap that reflects the expansion of NOAA reporting practice as much as the weather itself.
The costliest is flood, with $7.5M in reported property damage. In total, 8 distinct hazard types appear in this county archive, each listed with its own dated record below.
By hazard type
Every hazard type recorded in Stephenson County
| Hazard | Events | Deaths | Damage | Max | Span |
|---|---|---|---|---|---|
| Thunderstorm Wind | 261 | 0 | $4.8M | 90 | 1956–2026 |
| Hail | 135 | 0 | $173K | 3 | 1972–2026 |
| Flash Flood | 40 | 0 | $2.1M | 0 | 1997–2024 |
| Heavy Rain | 31 | 0 | $23K | 2 | 2003–2011 |
| Tornado | 23 | 0 | $3.0M | F2 | 1958–2026 |
| Flood | 13 | 0 | $7.5M | 0 | 1999–2019 |
| Funnel Cloud | 10 | 0 | $0 | 0 | 1998–2022 |
| Lightning | 5 | 0 | $65K | 0 | 1999–2018 |
Decade by decade
Stephenson County, Illinois severe weather history by decade
Reporting practice changed over time — early decades are undercounted, not calmer.
Tornado tracks
Paths crossing this county
20 mapped tornado paths intersect this county: 17 touched down inside it and 3 crossed in from a neighbouring county. This comes from path geometry, not county-tagged reports.
| Date | Scale | Deaths | Injuries | Path length | Origin |
|---|---|---|---|---|---|
| 1958-10-08 | EF2 | 1 | 0 | 81.0 mi | Touched down here |
| 2024-07-15 | EF2 | 0 | 0 | 15.4 mi | Crossed in |
| 2024-07-15 | EF1 | 0 | 0 | 29.8 mi | Crossed in |
| 2023-03-31 | EF1 | 0 | 0 | 11.0 mi | Crossed in |
| 2022-05-25 | EF1 | 0 | 0 | 1.8 mi | Touched down here |
| 2017-08-16 | EF1 | 0 | 0 | 2.8 mi | Touched down here |
| 1998-08-24 | EF1 | 0 | 0 | 0.5 mi | Touched down here |
| 1971-06-01 | EF1 | 0 | 0 | 0.1 mi | Touched down here |
| 1965-04-11 | EF1 | 0 | 40 | 27.1 mi | Touched down here |
| 1959-04-17 | EF1 | 0 | 0 | 2.0 mi | Touched down here |
Significant events
Deadliest events on record in Stephenson County
| Date | Type | Location | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Jul 31, 2008 | Thunderstorm Wind | WINSLOW | 0 | 1 | $25K |
| Jul 5, 2003 | Thunderstorm Wind | PEARL CITY | 0 | 1 | $20K |
| May 17, 1999 | Thunderstorm Wind | ORANGEVILLE | 0 | 1 | $40K |
| Aug 16, 1987 | Thunderstorm Wind | 0 | 1 | $0 |
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Heavy rainfall of 3 to over 12 inches over significant areas from 20 to 22 July in southern Wisconsin and Northern Illinois moved downstream causing the Rock River to rise well above major flood stage levels just downstream of Freeport down to the Mississippi at Moline. ||Freeport rose just below major flood stage level of 16.0 feet on July 23rd, 2017 at approximately 645 AM CST. It crested around 15.9 feet at approximately 10 AM CST on July 23rd, 2017 and fell below 15.5 feet at approximately 815 PM CST on July 25th.||Widespread river flooding and flash flooding resulted in a preliminary estimation of 7 to 8 million dollars in damage.
Torrential rains of 3 to 8 inches caused some flash flooding across parts of Stephenson County during the evening of July 27 and morning of July 28. There were reports of cattle scattered through county by flood waters with some washed downstream. The flood waters were several feet deep in the town of Pearl City. Two people died just west of Freeport, IL from carbon monoxide fumes from a generator use to pump water from a flooded basement.
Wind gusts estimated to be 65 to 75 mph caused widespread tree and structural damage in the vicinity of Freeport, IL between 630 pm and 655 pm August 4. On Rock City Rd, several trees and branches were blown down as well as a metal storage shed. In addition, twenty-five rows of corn on both sides of the road were flattened. Some buildings on the southwest side of town were damaged. On Fairview Rd, a tree was blown over onto a house. On Edwardsville Rd, some large tree limbs were blown down. A power outage was also observed across the county.
Context
Risk, population and federal disasters
Relatively Low
FEMA NRI risk rating
43,768
Population (ACS)
$135K
Median home value
14
Federal declarations
| Declared | Incident | Title | Type |
|---|---|---|---|
| Mar 26, 2020 | Biological | COVID-19 PANDEMIC | DR |
| Mar 13, 2020 | Biological | COVID-19 | EM |
| Sep 19, 2019 | Flood | SEVERE STORMS AND FLOODING | DR |
| Mar 17, 2011 | Snowstorm | SEVERE WINTER STORM AND SNOWSTORM | DR |
| Aug 19, 2010 | Severe Storm | SEVERE STORMS AND FLOODING | DR |
| Mar 13, 2008 | Snowstorm | RECORD SNOW AND NEAR RECORD SNOW | EM |
Within the county
Most affected places
- Freeport 170
Quick answers
Frequently asked
How many severe weather events have been recorded in Stephenson County, Illinois?
518 events are on record between 1956 and 2026, causing 0 direct deaths and $17.6M in property damage.
What is the most common severe weather hazard in Stephenson County?
Thunderstorm Wind, with 261 recorded events — 50.4% of everything in the archive for this county.
How many tornadoes have crossed Stephenson County?
20 mapped tornado paths intersect the county boundary; 17 of them touched down inside it. This is derived from path geometry, not county-tagged reports.
How many federal disaster declarations cover Stephenson County?
14 federal disaster declarations from FEMA include Stephenson County, each tied to a specific incident period.
How risky is Stephenson County compared with the rest of the country?
FEMA's National Risk Index rates Stephenson County as relatively low risk, placing it in the 74 percentile of its state for expected annual loss.
Where does the Stephenson County, Illinois severe weather history data come from?
Every figure is drawn from United States federal public-domain records: NOAA/NCEI Storm Events for the event archive, NOAA SPC SVRGIS for mapped tornado paths, FEMA for disaster declarations and risk ratings, and the U.S. Census for population context. Dates are shown in UTC and recent entries may still be revised by NOAA.
Nearby
Neighbouring counties
- Stark County 166
- Tazewell County 729
- Shelby County 312
- Union County 230
- Scott County 167
- Vermilion County 691
Cite this page
“Stephenson County, Illinois.” Severe Weather History. severeweatherhistory.com/county/illinois/stephenson-county/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.