3,229
Recorded events
102
Counties affected
25
Direct deaths
$2.5B
Property damage
Illinois flash flood history: 3,229 recorded events across 102 counties between 1996 and 2026.
Decade by decade
Illinois flash flood history by decade
The 2010s are the busiest decade on record with 1,238 reported flash flood events across Illinois. Earlier decades are thinner because systematic reporting for this hazard expanded over time, not because the weather was calmer.
County ranking
Counties with the most flash flood events in Illinois
| Rank | County | Events | Deaths | Damage | Span |
|---|---|---|---|---|---|
| #1 | Cook County | 191 | 1 | $1.5B | 1996–2026 |
| #2 | Sangamon County | 65 | 0 | $27.4M | 1996–2025 |
| #3 | Champaign County | 65 | 0 | $47.6M | 1996–2026 |
| #4 | Will County | 65 | 2 | $22.7M | 1996–2025 |
| #5 | DuPage County | 63 | 0 | $28.4M | 1996–2025 |
| #6 | Effingham County | 59 | 0 | $205K | 1996–2025 |
| #7 | Clay County | 57 | 0 | $9.1M | 1999–2025 |
| #8 | Vermilion County | 53 | 0 | $0 | 1996–2021 |
| #9 | Shelby County | 53 | 1 | $190K | 1996–2025 |
| #10 | Fulton County | 50 | 0 | $14.3M | 2000–2024 |
| #11 | Lake County | 47 | 0 | $18.3M | 1996–2024 |
| #12 | Christian County | 46 | 0 | $4.4M | 2000–2025 |
| #13 | Jo Daviess County | 45 | 3 | $15.4M | 1997–2026 |
| #14 | McDonough County | 45 | 0 | $391K | 1997–2025 |
| #15 | Jackson County | 44 | 0 | $874K | 1996–2024 |
| #16 | St. Clair County | 44 | 0 | $10.1M | 1996–2025 |
| #17 | Logan County | 43 | 0 | $1.5M | 1998–2023 |
| #18 | Macon County | 43 | 0 | $20.1M | 1996–2026 |
| #19 | Crawford County | 43 | 3 | $2.0M | 1996–2025 |
| #20 | Saline County | 42 | 0 | $4.5M | 1996–2025 |
| #21 | Coles County | 41 | 0 | $5.0M | 1999–2022 |
| #22 | Stephenson County | 40 | 0 | $2.1M | 1997–2024 |
| #23 | Williamson County | 40 | 0 | $1.9M | 1996–2025 |
| #24 | Jasper County | 40 | 0 | $190K | 1996–2022 |
| #25 | Peoria County | 39 | 0 | $130.0M | 1996–2023 |
Significant events
Deadliest flash flood events in Illinois
| Date | County | Scale | Deaths | Injuries |
|---|---|---|---|---|
| Dec 27, 2015 | Marion County | — | 5 | 0 |
| Jul 28, 2011 | Jo Daviess County | — | 3 | 0 |
| Aug 7, 2000 | Crawford County | — | 3 | 0 |
| Jul 18, 1996 | Will County | — | 2 | 0 |
| Jun 16, 2019 | Union County | — | 1 | 0 |
| Apr 18, 2013 | LaSalle County | — | 1 | 0 |
| Jul 15, 2024 | Winnebago County | — | 1 | 1 |
| Jun 16, 2013 | Brown County | — | 1 | 0 |
| Sep 20, 2009 | Morgan County | — | 1 | 0 |
| Sep 13, 2008 | Cook County | — | 1 | 0 |