Alert archive / Michigan

Weather alerts in Ontonagon County, Michigan

1,828 weather alerts since 1986, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Ontonagon County and its neighbors

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

Alerts
1,828
Warnings
526
Watches
265
Advisories
717
Busiest year
200799 alerts
Average year
49over 37 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 Ontonagon 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
2011010%
201910100%0

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
20087443%3100%37 min
20093167%0
20109456%5100%14 min
201118667%10100%29 min
20128275%540%46 min
20135180%1100%11 min
201420100%0
201530100%0
201620670%4100%25 min
20178450%2100%31 min
201815380%560%22 min
20194175%1100%29 min
202012375%367%38 min
202114471%250%27 min
202211191%450%4 min
20234325%3100%10 min
202414286%1100%14 min
202512467%10%

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2010110%1100%21 min
2016220%0
20182150%0
202210100%10%
2024110%1100%124 min
2025010%

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 7, 6:13 PM EDTSevere Thunderstorm WarningMQT47 min
Aug 7, 5:25 PM EDTSevere Thunderstorm WarningMQT45 min
Jul 27, 8:41 AM EDTSevere Thunderstorm WarningMQT27 min
Jul 27, 8:37 AM EDTSevere Thunderstorm WarningMQT30 min
Jul 27, 8:32 AM EDTSevere Thunderstorm WarningMQT38 min
Jul 27, 8:26 AM EDTSevere Thunderstorm WarningMQT64 min
Jul 27, 7:36 AM EDTSevere Thunderstorm WarningMQT54 min
Jul 20, 9:23 AM EDTSevere Thunderstorm WarningMQT67 min
Jul 20, 9:20 AM EDTSevere Thunderstorm WarningMQT55 min
Jul 20, 8:39 AM EDTSevere Thunderstorm WarningMQT66 min
Jul 12, 2:31 PM EDTExtreme Heat WarningMQT55 hr
Jun 29, 6:23 PM EDTSevere Thunderstorm WarningMQT22 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.