Alert archive / California

Weather alerts in Shasta County, California

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

Shasta County and its neighbors

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

Alerts
517
Warnings
125
Watches
9
Advisories
90
Busiest year
201948 alerts
Average year
14over 36 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 2009 to 2025, of tornado reports in Shasta 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
201610100%0
201910100%0
202510100%0

Severe thunderstorm warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2009100100%0
201030100%0
20123167%0
2013220%2100%2 min
20146350%650%21 min
201520100%10%
201610100%0
20173167%1100%18 min
20194250%1060%22 min
202010100%0
202350100%0
202430100%0
202520100%0

Flash flood warnings by year

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
2012030%
201310100%0
2014110%2100%234 min
2015010%
2019220%863%84 min
2021010%
2022010%
202320100%0
2024030%
2025110%1030%48 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 11, 10:02 AM PDTRed Flag WarningSTO3 days
Jun 18, 7:56 PM PDTRed Flag WarningSTO23 hr
Jun 12, 12:18 PM PDTExtreme Heat WarningSTO4 days
Jun 8, 9:18 AM PDTRed Flag WarningSTO3 days
May 15, 10:51 AM PDTRed Flag WarningSTO3 days
May 3, 4:47 PM PDTSevere Thunderstorm WarningSTO43 min
Apr 20, 8:56 AM PDTWinter Storm WarningSTO51 hr
Apr 9, 5:22 PM PDTSevere Thunderstorm WarningSTO38 min
Apr 9, 5:01 PM PDTSevere Thunderstorm WarningSTO29 min
Apr 9, 3:36 PM PDTSevere Thunderstorm WarningSTO14 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.