Hazard Mitigation Plan update · Section 4 draft · prepared October 3, 2026
Carroll County, Illinois Hazard Profiles
Draft. Built from public National Weather Service storm records (NOAA Storm Events, 1980 to June 2026). Not an adopted plan and not reviewed by FEMA.
Carroll County's plan, the Carroll County 2020 Hazard Mitigation Plan, expired January 11, 2026 in FEMA's plan-status data, with no update recorded as in progress on October 3, 2026. This chapter drafts the hazard-profile section of the update from 521 storm reports for the county, every one traceable to a NOAA event ID.
At a glance
7 hazards appear in the federal storm record for Carroll County. Winter storms are the most frequent; flooding accounts for the most recorded deaths and damage.
Hazard
Days with reports, 1996–2025
Years with at least one
Deaths*
Injuries*
Property damage entered*
Thunderstorm wind
91
29/30
0
2
$2.6M
Hail
35
21/30
0
0
$34K
Tornado
9
8/30
0
1
$2.3M
Flooding
43
23/30
0
0
$12.0M
Winter storms
159
30/30
0
0
$6K
Lightning
4
4/30
0
0
$90K
High wind (no storm)
14
9/30
0
0
$1.1M
* All years on record (tornado, wind and hail from the 1980s; other hazards from 1996). Dollars are as entered, not adjusted for inflation.
How often, year by year
Days with at least one report, 1996 to 2025. Each panel has its own scale. Hover a bar for the year.
Thunderstorm wind91 days · 29 of 30 yearsHail35 days · 21 of 30 yearsFlooding43 days · 23 of 30 yearsTornado9 days · 8 of 30 yearsWinter storms159 days · 30 of 30 yearsLightning4 days · 4 of 30 years
Show the numbers behind the charts
Year
Thunderstorm wind
Hail
Tornado
Flooding
Winter storms
Lightning
High wind (no storm)
1996
4
1
0
0
4
1
1
1997
2
2
0
2
5
0
3
1998
6
1
0
0
4
0
1
1999
4
2
1
1
6
1
0
2000
1
1
0
2
14
0
0
2001
2
0
0
3
9
0
2
2002
4
3
0
1
2
1
0
2003
2
1
1
1
3
0
2
2004
3
3
0
1
1
0
0
2005
4
0
0
0
1
0
0
2006
4
3
0
1
2
0
0
2007
5
2
0
2
16
0
0
2008
5
2
0
2
16
0
2
2009
2
2
0
3
7
0
0
2010
5
0
0
2
9
1
1
2011
4
1
0
4
5
0
0
2012
2
0
0
0
4
0
0
2013
1
0
2
1
8
0
0
2014
4
2
1
1
5
0
0
2015
0
1
1
2
5
0
0
2016
3
0
0
1
1
0
1
2017
2
0
0
3
2
0
0
2018
4
2
0
0
5
0
0
2019
3
0
0
5
5
0
1
2020
2
0
1
1
3
0
0
2021
4
1
0
0
6
0
0
2022
4
1
0
1
2
0
0
2023
1
2
1
1
4
0
0
2024
2
1
1
2
3
0
0
2025
2
1
0
0
2
0
0
When in the year
Days with reports by month, 1996 to 2025. Darker means more days.
J
F
M
A
M
J
J
A
S
O
N
D
Thunderstorm wind
4
3
13
24
19
18
7
2
1
Hail
2
8
8
6
5
5
1
Tornado
1
1
3
3
1
Flooding
2
8
5
11
12
3
1
1
Winter storms
45
37
14
3
1
7
52
Lightning
1
1
1
1
High wind (no storm)
4
2
3
2
2
1
Tornado tracks, 1984–2026
16 tornadoes. Lines run from touchdown to lift within the county; dots are tornadoes recorded at a single point. Hover a track for its date and rating.
F0/EF0F1/EF1F2/EF2F3 or strongerF5Unrated
County outline from the Census Bureau (simplified); community labels sit at the average location of reports naming them.
Hazard profiles
Each profile answers FEMA's questions for hazard identification: what it is, where, how bad (extent), what has happened, and how likely it is to happen again.
Tornado
Description
A violently rotating column of air in contact with the ground, rated after the fact on the Fujita scale (through January 2007) or the Enhanced Fujita scale, EF0 to EF5, by the damage it leaves.
Location
Countywide; tornado reports name 8 communities, most often Mt Carroll, Milledgeville and Lanark.
Extent
The strongest on record is the F3 of May 9, 1995 near Albany. Tornadoes rated F2/EF2 or stronger touched down on 2 separate days.
Previous occurrences
16 tornadoes on 13 days from 1984 to 2026. The busiest day was June 14, 2003, with 3. Weather Service survey, April 2, 2026: "A brief tornado developed northeast of Savanna with maximum winds near 90 mph. The tornado caused tree damage in a convergent path and also tossed and damaged a small shed."
Probability
At least one tornado in 8 of 30 years (27%) from 1996 to 2025.
Recorded losses
0 deaths, 1 injury, $2.3M in property damage as entered by the Weather Service (4 of 16 reports carry a dollar figure).
Severe thunderstorm wind
Description
Straight-line winds from thunderstorms, including downbursts, measured or estimated at 58 mph (50 knots) or more.
Location
Countywide; reports name 17 communities, most often Mt Carroll, Milledgeville and Savanna.
Extent
The highest gust on record is 90 knots (104 mph), estimated near Chadwick on June 23, 1996. 24 reports reached 65 knots (75 mph) or more.
Previous occurrences
198 reports on 115 days since 1980. September 25, 2018: "A severe thunderstorm with straight line winds estimated around 100 mph caused significant damage in the Milledgeville, Illinois area. Damage began around 3 miles SW of Milledgeville, and continued through the town. Damage included …"
Probability
Reports in 29 of 30 years (97%) from 1996 to 2025; about 3.0 damaging-wind days a year.
Recorded losses
0 deaths, 2 injuries, $2.6M in property damage as entered by the Weather Service (44 of 198 reports carry a dollar figure).
Hail
Description
Ice stones from thunderstorm updrafts; reported at 3/4 inch and larger in this record.
Location
Countywide; reports name 12 communities, most often Mt Carroll, Thomson and Lanark.
Extent
Largest: 3 inches near Thomson on April 2, 2026. 2 reports of 2 inches or more.
Previous occurrences
64 reports on 44 days since 1981.
Probability
Reports in 21 of 30 years (70%) from 1996 to 2025.
Recorded losses
0 deaths, 0 injuries, $34K in property damage as entered by the Weather Service (6 of 64 reports carry a dollar figure).
Flooding (river, flash and heavy rain)
Description
River flooding, and flash flooding when heavy rain overwhelms streets, ditches and small streams.
Location
Countywide; reports name 11 communities, most often Mt Carroll, Marcus and Savanna.
Extent
The costliest entry is July 24, 2010, at $10.0M in property damage.
Previous occurrences
59 flood, flash-flood and heavy-rain reports since 1997. April 15, 2026: "Report that Illinois Route 84 is closed from Savanna-Sabula Bridge north to the south entrance of the Mississippi Palisades State Park. The road is blocked with trees, other debris, and minor mudslides. Radar estimates …"
Probability
Reports in 23 of 30 years (77%) from 1996 to 2025.
Recorded losses
0 deaths, 0 injuries, $12.0M in property damage as entered by the Weather Service (16 of 59 reports carry a dollar figure).
Winter storms and ice
Description
Heavy snow, blizzards, ice storms, sleet and lesser winter weather, recorded by forecast zone rather than by point.
Location
Countywide (forecast-zone records).
Extent
Ice storms on 7 occasions. Zone records rarely give snow or ice totals; the full plan adds station data.
Previous occurrences
161 zone events from 1996 to 2026: 67 winter storm, 66 winter weather, 16 heavy snow, 7 ice storm, 5 blizzard.
Probability
Events in 30 of 30 years (100%) from 1996 to 2025.
Recorded losses
0 deaths, 0 injuries, $6K in property damage as entered by the Weather Service (2 of 161 reports carry a dollar figure).
Lightning
Description
Cloud-to-ground strikes that injure people, start fires or damage property. Only damaging strikes are recorded.
Location
Countywide; reports name 4 communities, most often Mt Carroll, Savanna and Chadwick.
Extent
0 deaths and 0 injuries on record.
Previous occurrences
4 damaging strikes since 1996.
Probability
Damaging strikes in 4 of 30 years (13%) from 1996 to 2025.
Recorded losses
0 deaths, 0 injuries, $90K in property damage as entered by the Weather Service (3 of 4 reports carry a dollar figure).
High wind (not from thunderstorms)
Description
Strong winds from large storm systems rather than thunderstorms, recorded by forecast zone.
Location
Countywide (forecast-zone records).
Extent
Highest: 60 knots (69 mph).
Previous occurrences
14 zone events since 1996.
Probability
Events in 9 of 30 years (30%) from 1996 to 2025.
Recorded losses
0 deaths, 0 injuries, $1.1M in property damage as entered by the Weather Service (4 of 14 reports carry a dollar figure).
Not covered by this record
Extreme heat, extreme cold, drought, earthquake and dam failure are not in the storm archive this chapter draws on. The full chapter profiles them from NOAA climate records, the U.S. Drought Monitor, USGS shaking maps and the state dam inventory, and the planning team decides which belong in the plan.
Previous occurrences by community
FEMA asks for hazard history for each participating jurisdiction. These are the communities the Weather Service names most often as the nearest place to a report.
Nearest community named in the report
Thunderstorm wind
Hail
Flooding
Tornado
Lightning
All
Mt Carroll
34
12
12
3
1
62
Savanna
26
7
10
2
1
46
Milledgeville
32
5
2
2
41
Lanark
20
8
3
2
1
34
Shannon
21
4
1
1
27
Thomson
11
8
2
21
Chadwick
9
3
4
1
17
Marcus
4
2
11
17
Wacker
4
2
2
8
Ms Pallisades Sp
2
4
6
Fairhaven
4
1
5
Hitt
2
2
4
Riverview
1
2
3
Ideal
2
1
3
Savanna Stransky Arp
1
1
2
Mount Carroll
1
1
Albany
1
1
Hazelhurst
1
1
What this draft covers, and what the full update adds
Covered here
Type, location and extent of each recorded hazard (FEMA review element B1).
Previous occurrences and probability of future events, countywide and by community (element B2).
Added in the full update
Vulnerability and impacts on people, buildings and critical facilities from county parcel and building data (element B3).
National Flood Insurance Program repetitive-loss properties from FEMA (element B4).
Planning-team meetings, public input, capability review, the mitigation strategy and adoption.
Data notes
Before 1996 the storm database records only tornado, thunderstorm wind and hail, so every rate on this page uses 1996–2025.
Recent reports rarely carry a damage estimate: 0 of 67 wind, hail, tornado and flood reports since 2019 do. A missing dollar figure means "not estimated," not "no damage."
Reports follow people. Towns with more spotters and roads show more reports.
Winter storm, high wind and some flood events are recorded by forecast zone, not by point.