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Hazard Mitigation Plan update · Section 4 draft · prepared October 3, 2026

DeKalb 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.

DeKalb County's plan, the DeKalb County 2021 Hazard Mitigation Plan, expired March 8, 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 574 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 DeKalb County. Thunderstorm wind is the most frequent; tornadoes account for the most recorded deaths and damage.

HazardDays with reports, 1996–2025Years with at least oneDeaths*Injuries*Property damage entered*
Thunderstorm wind12429/30016$1.3M
Hail5025/3000$0
Tornado1611/30211$8.0M
Flooding3721/3003$5.9M
Winter storms7726/3019$5K
Lightning44/3000$30K
High wind (no storm)1613/3000$72K

* 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 wind124 days · 29 of 30 years
0481996200520152025
Hail50 days · 25 of 30 years
0241996200520152025
Flooding37 days · 21 of 30 years
0241996200520152025
Tornado16 days · 11 of 30 years
0241996200520152025
Winter storms77 days · 26 of 30 years
05101996200520152025
Lightning4 days · 4 of 30 years
0121996200520152025
Show the numbers behind the charts
YearThunderstorm windHailTornadoFloodingWinter stormsLightningHigh wind (no storm)
19963212001
19972001101
19986202101
19996001300
20002201300
20013111011
20023003201
20038210102
20043312001
20056200110
20065300300
20077304600
20087103601
20092202300
20104201102
20114112110
20124100100
20134311100
20143300100
20150210301
20163100100
20174202000
20182201211
20191300702
20204132200
20216021500
20225203900
20235210301
20246231400
20256001600

When in the year

Days with reports by month, 1996 to 2025. Darker means more days.

JFMAMJJASOND
Thunderstorm wind26618362621612
Hail125912844221
Tornado1143331
Flooding211858633
Winter storms2324621417
Lightning1111
High wind (no storm)23111134

Tornado tracks, 1982–2026

24 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.

De KalbSycamoreSandwichDekalbWatermanShabbonaGenoaMaltaApril 9, 2015 · EF3 · 2 deaths
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 15 communities, most often Esmond, Fairdale and Kirkland.
Extent
The strongest on record is the EF3 of April 9, 2015 near Fairdale (2 deaths, 11 injuries). Tornadoes rated F2/EF2 or stronger touched down on 1 separate day.
Previous occurrences
24 tornadoes on 18 days from 1982 to 2026. The busiest day was August 9, 2021, with 5. Weather Service survey, August 9, 2021: "A tornado with peak winds of 105 mph touched down west of Fenstermaker Road and south of Bethany Road. Shortly after touching down, just east of Fenstermaker Road, the tornado produced a concentrated corridor of damage where two farm buildings were nearly completely destroyed. …"
Probability
At least one tornado in 11 of 30 years (37%) from 1996 to 2025.
Recorded losses
2 deaths, 11 injuries, $8.0M in property damage as entered by the Weather Service (3 of 24 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 29 communities, most often De Kalb, Sycamore and Sandwich.
Extent
The highest gust on record is 87 knots (100 mph), estimated near Malta on May 20, 2014. 31 reports reached 65 knots (75 mph) or more.
Previous occurrences
300 reports on 146 days since 1980. May 20, 2014: "An approximately seven mile swath of damage occurred on the south side of Dekalb which was consistent with 60 mph to occasionally 100 mph winds. Damage began near the intersection of Malta Road and Nelson Road and concluded near Lynch Road …"
Probability
Reports in 29 of 30 years (97%) from 1996 to 2025; about 4.1 damaging-wind days a year.
Recorded losses
0 deaths, 16 injuries, $1.3M in property damage as entered by the Weather Service (42 of 300 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 14 communities, most often De Kalb, Sycamore and Dekalb.
Extent
Largest: 2.75 inches near Sandwich on April 4, 2023. 3 reports of 2 inches or more.
Previous occurrences
87 reports on 62 days since 1980.
Probability
Reports in 25 of 30 years (83%) from 1996 to 2025.
Recorded losses
0 deaths, 0 injuries, $0 in property damage as entered by the Weather Service (0 of 87 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 18 communities, most often De Kalb, New Lebanon and Fairdale.
Extent
The costliest entry is September 14, 2008, at $3.0M in property damage.
Previous occurrences
52 flood, flash-flood and heavy-rain reports since 1996. June 11, 2026: "A few inches of standing water was reported on Quarry Road east of Fairdale Road due to flooding from farm fields and a nearby ditch. Six inches of standing water was reported on Route 72 near Ault Road."
Probability
Reports in 21 of 30 years (70%) from 1996 to 2025.
Recorded losses
0 deaths, 3 injuries, $5.9M in property damage as entered by the Weather Service (7 of 52 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 5 occasions. Zone records rarely give snow or ice totals; the full plan adds station data.
Previous occurrences
79 zone events from 1997 to 2026: 33 winter storm, 24 winter weather, 10 heavy snow, 6 blizzard, 5 ice storm, 1 sleet.
Probability
Events in 26 of 30 years (87%) from 1996 to 2025.
Recorded losses
1 death, 9 injuries, $5K in property damage as entered by the Weather Service (1 of 79 reports carries 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 3 communities, most often Sandwich, De Kalb and Sycamore.
Extent
0 deaths and 0 injuries on record.
Previous occurrences
4 damaging strikes since 2001.
Probability
Damaging strikes in 4 of 30 years (13%) from 1996 to 2025.
Recorded losses
0 deaths, 0 injuries, $30K in property damage as entered by the Weather Service (2 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: 63 knots (72 mph).
Previous occurrences
24 zone events since 1996.
Probability
Events in 13 of 30 years (43%) from 1996 to 2025.
Recorded losses
0 deaths, 0 injuries, $72K in property damage as entered by the Weather Service (6 of 24 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 reportThunderstorm windHailFloodingTornadoLightningAll
De Kalb432211177
Sycamore321221148
Sandwich29511238
Dekalb158326
Waterman1572226
Genoa162321
Malta1151118
Kirkland142218
Shabbona134118
Somonauk952117
Cortland123217
Hinckley12113
Fairdale513312
Rollo82111
New Lebanon2518
Wilkinson516
Hart415
Charter Grove55

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