Alert archive / Idaho

Weather alerts in Boise County, Idaho

1,376 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Boise County and its neighbors

Each county as a circle sized by its count since 1986. Tap one for its archive.

Alerts
1,376
Warnings
563
Watches
324
Advisories
243
Busiest year
2024100 alerts
Average year
36over 38 years on file

Over time

By year

Before late 2005 the archive holds only tornado, severe thunderstorm, flash flood and marine warnings, and from 1997 SPC's watches, so the jump that year is the archive widening, not the weather.

By month of the year

Warning verification

How often warnings here had a storm report inside them, and how much warning the reports had.

From 2008 to 2025, of tornado reports in Boise County fell inside a tornado warning, and 100% of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200910100%0
201010100%0

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2008110%650%13 min
2009110100%10%
20106267%10%
201110100%0
201220100%10%
20135260%250%19 min
201440100%0
2015110%0
201610100%0
20176183%0
20182150%0
2019110%0
20203233%20%
2021110%20%
20226183%1100%14 min
20233233%10%
202413469%475%27 min
2025040%

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
200810100%0
200910100%0
201030100%10%
201220100%0
20133233%4100%25 min
201480100%20%
201610100%0
201810100%0
2021110%0
202330100%0
2024030%
20253233%838%7 min

Years from 2008, the first full year of storm-based warnings. The year still running is on its own page.

Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.

By product

Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.

The latest warnings

The most recent on file, newest first.

IssuedProductOfficeLasted
Sep 18, 5:47 PM MDTFlash Flood Warning Considerable damage threatBOI118 min
Sep 18, 5:21 PM MDTFlash Flood Warning Considerable damage threatBOI2 hr
Sep 17, 4:31 AM MDTRed Flag WarningBOI16 hr
Aug 31, 1:37 PM MDTRed Flag WarningPIH47 hr
Aug 21, 5:20 PM MDTRed Flag WarningBOI31 hr
Aug 21, 12:41 PM MDTRed Flag WarningPIH32 hr
Aug 15, 7:02 PM MDTFlash Flood WarningBOI118 min
Aug 12, 1:30 PM MDTRed Flag WarningPIH32 hr
Aug 12, 1:20 PM MDTRed Flag WarningBOI3 days
Jul 31, 12:39 PM MDTRed Flag WarningBOI32 hr
Jul 31, 12:29 PM MDTRed Flag WarningPIH57 hr
Jul 23, 10:31 PM MDTFlash Flood Warning Considerable damage threatBOI119 min

Nearby

Alerts in force nowTornadoes on recordForecastThe radar archive

Sources

National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.