Alert archive / Montana

Weather alerts in Lake County, Montana

2,843 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Lake County and its neighbors

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

Alerts
2,843
Warnings
576
Watches
352
Advisories
1,497
Busiest year
2022176 alerts
Average year
75over 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, 0% of tornado reports in Lake County fell inside a tornado warning, and of the tornado warnings had no report inside them.

Tornado warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2023010%

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
20083233%5100%23 min
200910100%0
20105180%333%3 min
20113233%786%14 min
20129722%425%10 min
20136350%367%3 min
2015110%250%12 min
20163233%1100%13 min
2017010%
201920100%10%
2020220%250%4 min
202120100%10%
2022191237%1547%10 min
202310100%10%
20248625%956%21 min
202510100%10%

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
201010100%0
201220100%0
2019010%
2022030%
2024010%

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
Aug 6, 9:41 PM MDTRed Flag WarningMSO47 hr
Jul 31, 1:11 PM MDTRed Flag WarningMSO56 hr
Jun 29, 10:50 AM MDTAreal Flood WarningMSO24 hr
May 31, 7:42 PM MDTAreal Flood WarningMSO46 hr
Apr 24, 12:43 PM MDTFreeze WarningMSO43 hr
Mar 14, 4:57 PM MDTSnow Squall WarningMSO25 min
Mar 14, 3:56 PM MDTSnow Squall WarningMSO49 min
Mar 11, 9:21 AM MDTWinter Storm WarningMSO3 days
Mar 11, 9:21 AM MDTBlizzard WarningMSO24 hr
Mar 10, 11:52 AM MDTHigh Wind WarningMSO54 hr
Mar 10, 11:42 AM MDTWinter Storm WarningMSO4 days
Mar 6, 11:57 PM MSTHigh Wind WarningMSO46 hr

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.