Houses lie flooded from Hurricane Katrina September 11, 2005 in the Gentilly neighborhood of New Orleans, Louisiana.

States with the highest risk of flooding

Written by:
May 8, 2019
Jerry Grayson/Helifilms Australia PTY Ltd // Getty Images

States with the highest risk of flooding

It's spring, which means for much of the U.S., it's flood season. Warnings and watches have been pouring in from across the country, including current ones in Ohio, Illinois, Wisconsin, Idaho, Kansas, Oregon, Missouri, and more. And that's after earlier floods have already devastated communities this season—in Texas, two children and their mother were killed by a flash flood near a usually small creek. Some Iowa towns spent weeks underwater after the Missouri River flooded in March. Meanwhile, West Virginia and Louisiana are still struggling to recover after major floods from more than two years ago.

While it may seem like almost all of the country is at risk for being plunged underwater at any second, the flooding risk actually varies by state. Stacker wanted to know: which states are most likely to flood? In order to determine a ranking, we harnessed 2011 data from the Federal Emergency Management Agency's National Flood Hazard Layer and the agency's Designated Special Flood Hazard Area (SFHA) estimates. The National Flood Hazard Layer is a national database used to calculate the percentage of each county in the U.S. that qualifies as an SFHA; SFHA regions have a 1% annual chance of flooding.

All of the statistics were found through the CDC's National Environmental Public Health Tracking Network. Stacker first assessed the data provided on the county level, then added up all threatened land within each county to determine how much land was under threat in each state. The resulting ranking shows the states in order, from lowest to highest, of the percentage of each within FEMA's Designated Special Flood Hazard Area.

Although we may continually be fighting flooding events—and even more so as the climate continues to change—we are at least able to take some steps forward in predicting and combating them. Scientists are starting to use drones, supercomputers, and sonar to predict where rivers will overflow and to help monitor flood control projects. Generally speaking, we have a glimmer of hope.

Read on to find out how your state ranks.

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#51. Alaska

Percentage of state within flood hazard area: 0.5%
Total flood hazard area: 1,286 square miles (#42 among all states)

#50. Wyoming

Percentage of state within flood hazard area: 1.6%
Total flood hazard area: 1,462 square miles (#41 among all states)

#49. Hawaii

Percentage of state within flood hazard area: 1.81%
Total flood hazard area: 124 square miles (#50 among all states)

#48. Idaho

Percentage of state within flood hazard area: 1.89%
Total flood hazard area: 1,589 square miles (#39 among all states)

#47. Montana

Percentage of state within flood hazard area: 1.89%
Total flood hazard area: 2,485 square miles (#32 among all states)

#46. Colorado

Percentage of state within flood hazard area: 2.04%
Total flood hazard area: 1,890 square miles (#38 among all states)

#45. Utah

Percentage of state within flood hazard area: 2.72%
Total flood hazard area: 1,944 square miles (#37 among all states)

#44. Nevada

Percentage of state within flood hazard area: 2.74%
Total flood hazard area: 2,981 square miles (#28 among all states)

#43. New Mexico

Percentage of state within flood hazard area: 2.76%
Total flood hazard area: 2,966 square miles (#29 among all states)

#42. Oregon

Percentage of state within flood hazard area: 3.32%
Total flood hazard area: 3,231 square miles (#26 among all states)

#41. North Dakota

Percentage of state within flood hazard area: 3.36%
Total flood hazard area: 1,993 square miles (#36 among all states)

#40. Arizona

Percentage of state within flood hazard area: 3.52%
Total flood hazard area: 4,014 square miles (#21 among all states)

#39. South Dakota

Percentage of state within flood hazard area: 3.89%
Total flood hazard area: 2,217 square miles (#34 among all states)

#38. West Virginia

Percentage of state within flood hazard area: 4.02%
Total flood hazard area: 975 square miles (#44 among all states)

#37. Michigan

Percentage of state within flood hazard area: 4.67%
Total flood hazard area: 2,534 square miles (#31 among all states)

#36. Washington

Percentage of state within flood hazard area: 4.73%
Total flood hazard area: 3,247 square miles (#25 among all states)

#35. Pennsylvania

Percentage of state within flood hazard area: 5.29%
Total flood hazard area: 2,398 square miles (#33 among all states)

#34. Ohio

Percentage of state within flood hazard area: 6.9%
Total flood hazard area: 2,855 square miles (#30 among all states)

#33. California

Percentage of state within flood hazard area: 7.2%
Total flood hazard area: 11,434 square miles (#5 among all states)

#32. Minnesota

Percentage of state within flood hazard area: 7.2%
Total flood hazard area: 5,627 square miles (#16 among all states)

#31. Vermont

Percentage of state within flood hazard area: 7.33%
Total flood hazard area: 705 square miles (#45 among all states)

#30. New Hampshire

Percentage of state within flood hazard area: 7.43%
Total flood hazard area: 690 square miles (#46 among all states)

#29. New York

Percentage of state within flood hazard area: 7.53%
Total flood hazard area: 3,715 square miles (#24 among all states)

#28. Iowa

Percentage of state within flood hazard area: 8.17%
Total flood hazard area: 4,541 square miles (#18 among all states)

#27. Nebraska

Percentage of state within flood hazard area: 8.88%
Total flood hazard area: 5,450 square miles (#17 among all states)

#26. Maine

Percentage of state within flood hazard area: 9.04%
Total flood hazard area: 3,058 square miles (#27 among all states)

#25. Kansas

Percentage of state within flood hazard area: 9.1%
Total flood hazard area: 6,487 square miles (#13 among all states)

#24. Kentucky

Percentage of state within flood hazard area: 9.63%
Total flood hazard area: 3,879 square miles (#22 among all states)

#23. Virginia

Percentage of state within flood hazard area: 9.83%
Total flood hazard area: 4,043 square miles (#20 among all states)

#22. Connecticut

Percentage of state within flood hazard area: 10.14%
Total flood hazard area: 511 square miles (#47 among all states)

#21. Oklahoma

Percentage of state within flood hazard area: 10.28%
Total flood hazard area: 7,075 square miles (#11 among all states)

#20. Wisconsin

Percentage of state within flood hazard area: 10.29%
Total flood hazard area: 5,746 square miles (#15 among all states)

#19. Indiana

Percentage of state within flood hazard area: 10.32%
Total flood hazard area: 3,737 square miles (#23 among all states)

#18. Tennessee

Percentage of state within flood hazard area: 10.5%
Total flood hazard area: 4,424 square miles (#19 among all states)

#17. Texas

Percentage of state within flood hazard area: 10.97%
Total flood hazard area: 27,752 square miles (#1 among all states)

#16. Massachusetts

Percentage of state within flood hazard area: 11.77%
Total flood hazard area: 993 square miles (#43 among all states)

#15. Illinois

Percentage of state within flood hazard area: 12.27%
Total flood hazard area: 6,916 square miles (#12 among all states)

#14. Rhode Island

Percentage of state within flood hazard area: 14.78%
Total flood hazard area: 172 square miles (#49 among all states)

#13. Alabama

Percentage of state within flood hazard area: 14.93%
Total flood hazard area: 7,736 square miles (#10 among all states)

#12. Missouri

Percentage of state within flood hazard area: 15.06%
Total flood hazard area: 10,415 square miles (#7 among all states)

#11. Georgia

Percentage of state within flood hazard area: 15.19%
Total flood hazard area: 8,963 square miles (#8 among all states)

#10. North Carolina

Percentage of state within flood hazard area: 17.13%
Total flood hazard area: 8,765 square miles (#9 among all states)

#9. District of Columbia

Percentage of state within flood hazard area: 17.71%
Total flood hazard area: 12 square miles (#51 among all states)

#8. Delaware

Percentage of state within flood hazard area: 19.12%
Total flood hazard area: 391 square miles (#48 among all states)

#7. Maryland

Percentage of state within flood hazard area: 19.17%
Total flood hazard area: 2,097 square miles (#35 among all states)

#6. South Carolina

Percentage of state within flood hazard area: 19.2%
Total flood hazard area: 5,993 square miles (#14 among all states)

#5. New Jersey

Percentage of state within flood hazard area: 19.27%
Total flood hazard area: 1,517 square miles (#40 among all states)

#4. Arkansas

Percentage of state within flood hazard area: 22.57%
Total flood hazard area: 12,051 square miles (#4 among all states)

#3. Mississippi

Percentage of state within flood hazard area: 23.14%
Total flood hazard area: 11,068 square miles (#6 among all states)

#2. Florida

Percentage of state within flood hazard area: 40.08%
Total flood hazard area: 23,976 square miles (#3 among all states)

#1. Louisiana

Percentage of state within flood hazard area: 50.56%
Total flood hazard area: 24,792 square miles (#2 among all states)

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