Wyoming floods
Every recorded flood since 1996 · 23 counties with a record
NOAA's Storm Events Database records 568 floods and flash floods in Wyoming from 1996 through June 30, 2026, about 20 a year since 2000. The deadliest was the July 19, 2011 flash flood in Carbon County: 4 deaths and 2 injuries. Wyoming ranks 50th of 52 states and territories by count and 50th of 51 per square mile.
Floods in Wyoming, 1996 to 2026
Flood records per year (NOAA Storm Events); 2026 to June 30, 2026.
- recorded, no damage figure
- under $1 million
- $1 million or more
- $10 million or more
- $100 million or more, or 10 deaths
- $1 billion or more, or 100 deaths
- a year's colour: its recorded damage or deaths
- a year with a death
- Records
- 5681996 to June 30, 2026
- A year since 2000
- 20average
- Deaths
- 66 injuries
- Damage, 2025 dollars
- $82Mas filed
- Busiest year
- 201152 records
Source: NOAA NCEI Storm Events Database, records through June 30, 2026; deaths and damage as filed, damage in 2025 dollars. Search the record at NCEI.
Are floods and flash floods common in Wyoming?
Wyoming averages about 20 floods and flash floods a year since 2000, 50th of 52 states and territories by count. The busiest year on record was 2011 (52). Per 10,000 square miles of land, Wyoming records 59 floods and flash floods since 1996, 50th of 51 states and territories by that measure.
Source: NOAA NCEI Storm Events Database, records since 1996, per 10,000 square miles of land area (Census Bureau 2024 Gazetteer; places under 1,000 square miles not ranked). Damage colours: Storm Events damage, 2025 dollars.
Which counties in Wyoming have the most floods and flash floods?
Per square mile, Laramie County leads Wyoming: 61 days with a flood since 1996, 22.7 per 1,000 square miles of land. By raw count, Laramie County has the most flood records (94 since 1996); large counties collect more records simply by covering more ground, so the ranking counts days with a record per unit of area (a storm filed for several forecast zones adds several records but one day).
Source: NOAA NCEI Storm Events Database, days with a record in the county since 1996 per 1,000 square miles of land (Census Bureau 2024 Gazetteer); in brackets, the count of records.
When is flood season in Wyoming?
57% of its floods and flash floods since 1996 fell in June and July. The busiest month is June (165 records).
The values, month by month
Jan 2 · Feb 10 · Mar 15 · Apr 3 · May 111 · Jun 165 · Jul 161 · Aug 78 · Sep 20 · Oct 1 · Nov 0 · Dec 2 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began, since 1996.
What were the deadliest floods and flash floods in Wyoming?
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2011-07-19 | Flash FloodRyan Park, Carbon County Thunderstorms with heavy rain moved across the Snowy Range and Brush Creek area on State Highway 130 between 9 pm and midnight on July 18. Debris carried down Brush Creek by runoff from the heavy rainfall clogged the drainage culvert at milepost 55.8 on State Highway 130, about 13 miles east of the junction with State ... | 4 | 2 | – | |
| 2008-07-22 | Flash FloodRecluse, Campbell County Water rushing down a canyon washed out a culvert and a small section of Trail Creek Road east of Highway 59. A pickup truck drove into the washed out section of road, resulting in one fatality and three injuries. | 1 | 3 | – | |
| 2017-02-21 | FloodRiverton, Fremont County Law enforcement reported flooding ditches and sheet flooding north of Riverton on the evening of February 21st. A 33-year old man fell into the flood waters and drowned. A Coroners report noted that the man was under the influence of alcohol, marijuana, amphetamines and anti-depressants. | 1 | 0 | $12K |
Source: NOAA NCEI Storm Events Database: deaths direct and indirect, as filed by the National Weather Service, summed over each storm (one episode, or one named storm filed by several offices). Storm names from the titles of FEMA declarations that name the storm's counties.
The costliest floods and flash floods in Wyoming
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2022-06-12 | FloodMt Washburn, Park County | 0 | 0 | $25M | |
| 2010-06-04 | FloodSinks Canyon Sp, Fremont County | 0 | 0 | $16M | |
| 2009-07-03 | Flash FloodMountain View, Natrona County | 0 | 1 | $6.9M | |
| 2023-06-15 | Flash FloodBessemer Bend, Natrona County | 0 | 0 | $2.8M | |
| 2017-06-04 | FloodRiverton Regional A, Fremont County | 0 | 0 | $2.4M | |
| 2015-05-24 | Flash FloodThermopolis, Hot Springs County One storm episode: 2 records in 2 places; the totals are the episode's. | 0 | 0 | $2.2M | |
| 2013-09-12 | Flash FloodLa Barge, Lincoln County | 0 | 0 | $1.9M | |
| 2015-06-04 | Flash FloodVan Tassell, Niobrara County | 0 | 0 | $1.9M |
Source: NOAA NCEI Storm Events Database: property and crop damage as estimated by the National Weather Service, in 2025 dollars.
Are floods and flash floods becoming more frequent in Wyoming?
Wyoming's count per decade against the whole country's, and its share. NOAA recorded every event type only from 1996, so earlier decades are not comparable; the share of the national total is the fairer comparison across decades.
| Decade | Wyoming | United States | Wyoming's share |
|---|---|---|---|
| 1996-99 | 55 | 20,986 | 0.26% |
| 2000s | 120 | 54,913 | 0.22% |
| 2010s | 306 | 68,322 | 0.45% |
| 2020-26 | 87 | 43,563 | 0.20% |
Source: NOAA NCEI Storm Events Database.
The most recent floods and flash floods in Wyoming
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2026-06-25 | Flash FloodWheatland, Platte County | 0 | 0 | $6K | |
| 2026-06-01 | Flash FloodFort Laramie, Goshen County | 0 | 0 | $20K | |
| 2025-08-27 | Flash FloodJeffrey City, Fremont County | 0 | 0 | – | |
| 2025-07-30 | Flash FloodMoneta, Fremont County | 0 | 0 | $20K | |
| 2025-07-24 | Flash FloodArcola, Laramie County | 0 | 0 | – | |
| 2025-07-23 | Flash FloodCheyenne, Laramie County | 0 | 0 | – | |
| 2025-07-23 | Flash FloodCheyenne Airport, Laramie County | 0 | 0 | – | |
| 2025-07-23 | Flash FloodCheyenne, Laramie County | 0 | 0 | – | |
| 2025-07-23 | Flash FloodCheyenne, Laramie County | 0 | 0 | – | |
| 2025-06-02 | Flash FloodSlater, Platte County | 0 | 0 | $20K | |
| 2023-06-15 | Flash FloodBessemer Bend, Natrona County | 0 | 0 | $2.8M | |
| 2022-06-12 | FloodMt Washburn, Park County | 0 | 0 | $25M |
Source: NOAA NCEI Storm Events Database, records through June 30, 2026; the newest months are revised by NCEI as reports arrive. Search the record at NCEI.
Federal disaster declarations for floods and flash floods in Wyoming
FEMA has declared 8 disasters in Wyoming for floods and flash floods, counting its incident type and declarations that name flood in the title (FEMA files most storm disasters under Severe Storm); 8 were major disasters, the latest on September 11, 2023.
| Declared | Number | Title | Areas named |
|---|---|---|---|
| 2023-09-11 | DR-4739 | Flooding | 1 |
| 2017-08-05 | DR-4327 | Flooding | 3 |
| 2015-07-07 | DR-4227 | Severe Storms and Flooding | 4 |
| 2011-07-22 | DR-4007 | Severe Storms, Flooding, and Landslides | 16 |
| 2010-07-14 | DR-1923 | Flooding | 3 |
| 1985-08-07 | DR-740 | Severe Storms, Hail & Flooding | 1 |
| 1978-05-29 | DR-557 | Severe Storms, Flooding & Mudslides | 12 |
| 1963-07-04 | DR-155 | Heavy Rains & Flooding | 1 |
Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), through October 2, 2026. OpenFEMA dataset page.
Next
- Laramie County: the county's whole recordThe Wyoming county with the most floods and flash floods per square mile
- Floods across the United StatesEvery state ranked, by year and month
- Every natural hazard in WyomingTornadoes, floods, storms, heat and the federal declarations
- High wind and dust storms in Wyoming8,737 records
- Winter storms in Wyoming7,057 records
- Hail in Wyoming4,924 records