National Weather ServiceIdahoFlash Flood WarningArchive to October 1, 2026
Flash Flood Warnings in Idaho
The National Weather Service issued 10 flash flood warnings for Idaho in 2025 and 21 a year on average in 2008-2025; in 2021-2025 it had the 38th most of any state. 2026 through September: 26, 26% above the average of 21 for those months in 2008-2025. Blaine was covered most often (61 times since 2008).
How many flash flood warnings does Idaho get?
Every flash flood warning that covered part of Idaho. 2026 is an outline: the year is not over.
The numbers
| Year | Count |
|---|---|
| 2026 (through September) | 26 |
| 2025 | 10 |
| 2024 | 4 |
| 2023 | 58 |
| 2022 | 11 |
| 2021 | 34 |
| 2020 | 1 |
| 2019 | 6 |
| 2018 | 3 |
| 2017 | 7 |
| 2016 | 4 |
| 2015 | 14 |
| 2014 | 78 |
| 2013 | 57 |
| 2012 | 5 |
| 2011 | 13 |
| 2010 | 16 |
| 2009 | 47 |
| 2008 | 8 |
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
When in the year does Idaho get them?
Sum of 2008-2025; the busiest month is labelled.
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
Where in Idaho?
| County or forecast zone | Since 2008 | Since 2023 | Last issued |
|---|---|---|---|
| Blaine | 61 | 12 | September 18, 2026 |
| Bannock | 50 | 8 | July 16, 2026 |
| Cassia | 46 | 13 | June 14, 2023 |
| Power | 41 | 6 | August 16, 2026 |
| Elmore | 39 | 4 | September 18, 2026 |
| Boise | 32 | 11 | September 18, 2026 |
| Custer | 24 | 9 | September 18, 2026 |
| Bingham | 23 | 7 | August 16, 2026 |
| Lemhi | 23 | 7 | July 31, 2025 |
| Owyhee | 21 | 2 | August 15, 2026 |
| Oneida | 19 | 1 | May 26, 2023 |
| Camas | 18 | 1 | August 4, 2023 |
The NWS issues these products for counties or forecast zones; a zone can be part of a county or a mountain range.
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
The latest flash flood warnings for Idaho in AreaZine's record
NWS BoiseWarningSeptember 18, 2026
Flash Flood Warning: Boise, ID
Expired 8:15 p.m. MDT, September 18, 2026
NWS BoiseWarningSeptember 18, 2026
Flash Flood Warning: Boise, ID
Expired 8:15 p.m. MDT, September 18, 2026
NWS PocatelloWarningSeptember 18, 2026
Flash Flood Warning: Blaine, Butte and Custer, ID
Expired 4:30 p.m. MDT, September 18, 2026
NWS BoiseWarningSeptember 18, 2026
Flash Flood Warning: Elmore, ID
Expired 2:00 p.m. MDT, September 18, 2026
NWS PocatelloWarningSeptember 18, 2026
Flash Flood Warning: Jefferson and Madison, ID
Expired 1:45 p.m. MDT, September 18, 2026
NWS PocatelloWarningSeptember 18, 2026
Flash Flood Warning: Blaine, ID
Expired 12:15 p.m. MDT, September 18, 2026
NWS PocatelloWarningSeptember 17, 2026
Flash Flood Warning: Jefferson and Madison, ID
Expired 2:30 a.m. MDT, September 18, 2026
NWS PocatelloWarningSeptember 17, 2026
Flash Flood Warning: Bonneville and Jefferson, ID
Expired 2:00 a.m. MDT, September 18, 2026
This list is AreaZine's record of the NWS alert feed, kept since April 6, 2026; the counts above come from the complete IEM archive.
Source: National Weather Service alerts (api.weather.gov).
What is a flash flood warning?
A flash flood warning means flash flooding is happening or about to happen: water rising fast in streams, streets or dry washes, usually within six hours of heavy rain or a dam or levee failure. A warning means the hazard is happening, about to happen, or very likely: act now to protect people and property. The national record · Every warning type in Idaho.