Flood events in Lewis and Clark County, Montana The flood events on record, by date and by year
This page is a county record of past events and claims. It does not show the flood zone or the risk of an address. For the flood map of an address, use FEMA's address search (opens in a new tab).
NCEI has 39 flood events on record for Lewis and Clark County, Montana, from 1996 through 30 Jun 2026.
The newest flood event on record is on 11 Sep 2024.
From 2016 through 2025, NCEI has 21 flood events on record for the county.
The NWS collects event reports from a variety of sources, which include (but are not limited to): county, state, and federal emergency management officials, local law enforcement officials, SKYWARN spotters, NWS damage surveys, newspaper clipping services, the insurance industry, and the general public, among others.
The National Weather Service reports property and crop damage estimates using available data at the time of event reporting. These values should therefore be considered broad estimates. Damage amounts are not adjusted for inflation.
Zone (NWS Forecast Zone): A zone is a geographic area defined by the NWS for issuing forecasts, watches, and warnings. While zones often align with counties, they can also represent smaller or subdivided areas within a county to account for differences in weather conditions, such as elevation or proximity to water. Larger-scale events—such as heat, cold, drought, and winter storms—are typically recorded by zone.
The words of the agency. Source: NOAA NCEI, Storm Events Database, page "Frequently Asked Questions", copied on .
Date of the data: NCEI storm events through . Event types on this page: Flood, Flash Flood, Coastal Flood, Lakeshore Flood.
Newest flood events on record
Flash Flood
1 mile NNW of CANYON FERRY
Flash Flood
3 miles NW of MARYSVILLE
Flood
5 miles SSW of MID CANON
Flood
4 miles SW of BIRDSEYE. Damage estimate: $100 thousand
Flash Flood
1 mile E of HELENA
Flash Flood
1 mile NW of HELENA
Flash Flood
1 mile NW of HELENA. Damage estimate: $700 thousand
Flood
11 miles NW of CRAIG
Flood
1 mile NNW of AUGUSTA ARPT
Flood
6 miles E of LINCOLN ARPT
Flood
15 miles ENE of LINCOLN ARPT
Flood
4 miles NNE of CRAIG
Flood
1 mile ENE of FT HARRISON
Flood
1 mile WSW of AUGUSTA
Flood
4 miles NW of LINCOLN ARPT
Flood
8 miles SE of LINCOLN ARPT
Flash Flood
1 mile NE of HELENA
Flood
3 miles SE of IRON
Flood
3 miles WNW of LINCOLN
Flood
2 miles ENE of FT HARRISON
Flood
At FT HARRISON
Flood
43 miles NW of AUGUSTA
Flash Flood
5 miles N of HELENA
Flash Flood
2 miles N of BIRDSEYE
Flash Flood
1 mile NNE of FT HARRISON. Damage estimate: $50 thousand
A place is the text of the NCEI record: a distance and a direction from a reference place. The site does not show a place text that names a private property or reads as a person. NCEI gives no magnitude for this hazard.
Flood events by year
| Decade | Year that ends in 0 | Year that ends in 1 | Year that ends in 2 | Year that ends in 3 | Year that ends in 4 | Year that ends in 5 | Year that ends in 6 | Year that ends in 7 | Year that ends in 8 | Year that ends in 9 | All |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1950s | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1960s | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1970s | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1980s | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1990s | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
| 2000s | 0 | 5 | 3 | 0 | 2 | 0 | 0 | 0 | 1 | 1 | 12 |
| 2010s | 0 | 1 | 1 | 2 | 1 | 0 | 0 | 0 | 12 | 1 | 18 |
| 2020s | 1 | 0 | 3 | 3 | 1 | 0 | 0 (part of the year) | 8 |
A darker cell has a larger count. The number is in each cell.
Flood and flash flood events are on record from 1996. The year 2026 has the events through 30 Jun 2026 only.
By month, all years
- Jan0 events
- Feb0 events
- Mar1 event
- Apr4 events
- May7 events
- Jun13 events
- Jul8 events
- Aug5 events
- Sep1 event
- Oct0 events
- Nov0 events
- Dec0 events
Beside the other counties
| Measure | Lewis and Clark | All counties of Montana | All counties of the United States |
|---|---|---|---|
| Flood events, 1996 to 2026 | 39 | 1,094 | 177,902 |
| Events for each 100 square miles | 1.1 | 0.8 | 5.0 |
| Events for each 10,000 residents | 5.4 | 9.9 | 5.4 |
The columns for the state and the United States total the counties. They count the events of each county in the same way as the county column. A forecast zone with another name than a county counts for the state only.
More flood events on record
| Date | Event type | Magnitude | Damage estimate | Deaths | Injuries | On record for |
|---|---|---|---|---|---|---|
| Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | none | 0 | 0 | County | |
| Flash Flood | not recorded | $5 thousand | 0 | 0 | County | |
| Flash Flood | not recorded | $4 thousand | 0 | 0 | County |
The table has all other events on record. A damage figure is an estimate in the NCEI record.
Official channels
- NCEI Storm Events Database (opens in a new tab)Search the full NCEI record by state, county and date.
- National Weather Service: Great Falls, MT (opens in a new tab)The forecast office that issues the weather warnings for the county.
- FEMA Flood Map Service Center: Search By Address (opens in a new tab)Search an address to see its flood map. This site has no flood-zone data.
These links open the pages of the agencies. The site checked the links on .
Cite this page
County Hazards. "Flood events on record for Lewis and Clark County, Montana". https://countyhazards.com/county/mt/lewis-and-clark/flood/. Data: NOAA NCEI Storm Events Database through 30 Jun 2026. Page made on .
Questions
- Which month has the most flood events on record for Lewis and Clark County?
- June has 13 of the 39 flood events on record from 1996 through 30 Jun 2026.
- How many flood events are on record for Montana?
- NCEI has 1,175 flood events on record for Montana from 1996 through 30 Jun 2026. That count has every forecast zone of the state.
- How does Lewis and Clark County compare with the other counties of Montana?
- The counties of Montana have 0.8 flood events for each 100 square miles. Lewis and Clark County has 1.1.