Alert archive / California / Flash Flood Warnings

Flash Flood Warnings in California, 2024

129 flash flood warnings in 2024. An alert counts here when it covered any part of the state, so the counties below add up to more than the state. The archive of flash flood warnings reaches back to 1986.

Flash Flood Warnings by county

Each county as a circle sized by its count in 2024. Tap one for its archive.

Flash Flood Warnings: 129
Busiest month: July44 flash flood warnings
Busiest day: July 15, 202410 flash flood warnings

Over time

By month

Warning verification

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

41 of 129 flash flood warnings covering California in 2024 had a flash flood report inside them; 179 of 600 flash flood reports fell inside a warning, on average 164 minutes after it went out.

California, 2024

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Flash flood warnings	129	41	68%	600	30%	164 min

Each office's whole area, 2024

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Eureka, CA: flash flood warnings	2	0	100%	215	0%
NWS Hanford, CA: flash flood warnings	7	0	100%	9	0%
NWS San Francisco Bay Area, CA: flash flood warnings	6	1	83%	83	1%	63 min
NWS San Diego, CA: flash flood warnings	32	5	84%	42	43%	73 min
NWS Phoenix, AZ: flash flood warnings	49	11	78%	12	100%	63 min
NWS Sacramento, CA: flash flood warnings	9	1	89%	19	5%	96 min
NWS Las Vegas, NV: flash flood warnings	63	15	76%	34	56%	60 min
NWS Los Angeles, CA: flash flood warnings	34	22	35%	201	72%	189 min
NWS Reno, NV: flash flood warnings	10	0	100%	7	0%

An office's figures cover every county it serves, including across state lines.

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.

The alerts

Every alert, in the order issued. Times are local, Pacific Time. Each opens its own page with the text, the map, the radar and the sounding.

Issued	Product	Office	Counties	Lasted
Jan 13, 11:18 AM PST	Flash Flood Warning Considerable damage threat	EKA	Del Norte	3 hr
Jan 22, 8:21 AM PST	Flash Flood Warning Considerable damage threat	SGX	San Diego	5 hr
Jan 22, 9:34 AM PST	Flash Flood Warning Considerable damage threat	SGX	San Diego	3 hr
Jan 22, 10:31 AM PST	Flash Flood Warning Considerable damage threat	SGX	San Diego	2 hr
Feb 1, 8:12 AM PST	Flash Flood Warning	LOX	Los Angeles	3 hr
Feb 1, 11:49 AM PST	Flash Flood Warning Considerable damage threat	SGX	San Diego	116 min
Feb 1, 4:32 PM PST	Flash Flood Warning	HNX	Kern	77 min
Feb 4, 2:40 PM PST	Flash Flood Warning	LOX	Santa Barbara, Ventura	9 hr
Feb 4, 2:58 PM PST	Flash Flood Warning	LOX	San Luis Obispo, Santa Barbara	8 hr
Feb 4, 3:41 PM PST	Flash Flood Warning	LOX	Los Angeles	8 hr
Feb 4, 4:51 PM PST	Flash Flood Warning	LOX	Los Angeles	7 hr
Feb 4, 11:38 PM PST	Flash Flood Warning Considerable damage threat	LOX	Los Angeles	9 hr
Feb 5, 1:13 AM PST	Flash Flood Warning	LOX	Los Angeles, Ventura	8 hr
Feb 5, 1:33 AM PST	Flash Flood Warning	SGX	San Bernardino	3 hr
Feb 5, 4:21 AM PST	Flash Flood Warning	SGX	San Bernardino	3 hr
Feb 5, 9:40 AM PST	Flash Flood Warning	LOX	Los Angeles, Ventura	11 hr
Feb 5, 1:08 PM PST	Flash Flood Warning	LOX	Los Angeles, Ventura	8 hr
Feb 5, 8:50 PM PST	Flash Flood Warning	LOX	Los Angeles, Ventura	13 hr
Feb 5, 9:33 PM PST	Flash Flood Warning	SGX	Orange, Riverside, San Diego	117 min
Feb 6, 7:42 AM PST	Flash Flood Warning Considerable damage threat	SGX	Orange	4 hr
Feb 6, 9:24 AM PST	Flash Flood Warning Considerable damage threat	LOX	Los Angeles	3 hr
Feb 6, 9:55 AM PST	Flash Flood Warning Considerable damage threat	SGX	Orange, Riverside, San Diego	3 hr
Feb 7, 7:15 PM PST	Flash Flood Warning Considerable damage threat	LOX	Los Angeles, Ventura	3 hr
Feb 7, 8:55 PM PST	Flash Flood Warning	LOX	Los Angeles	2 hr
Feb 19, 1:58 AM PST	Flash Flood Warning	LOX	Santa Barbara, Ventura	9 hr
Feb 19, 4:00 AM PST	Flash Flood Warning	LOX	Santa Barbara	7 hr
Feb 19, 4:01 AM PST	Flash Flood Warning	LOX	Ventura	14 hr
Feb 19, 7:10 AM PST	Flash Flood Warning	LOX	Los Angeles, Ventura	11 hr
Feb 20, 1:57 PM PST	Flash Flood Warning	MTR	City and County of San Francisco	111 min
Feb 21, 1:55 AM PST	Flash Flood Warning	LOX	Los Angeles, Ventura	4 hr
Feb 21, 1:56 AM PST	Flash Flood Warning Considerable damage threat	LOX	Los Angeles, Ventura	4 hr
Feb 21, 2:23 AM PST	Flash Flood Warning	LOX	Los Angeles	4 hr
Mar 6, 12:31 PM PST	Flash Flood Warning	MTR	Monterey	59 min
Mar 6, 5:35 PM PST	Flash Flood Warning	LOX	Los Angeles	3 hr
Mar 7, 4:00 PM PST	Flash Flood Warning	LOX	Los Angeles, Ventura	105 min
Mar 7, 4:06 PM PST	Flash Flood Warning Considerable damage threat	LOX	Los Angeles	3 hr
Mar 7, 4:28 PM PST	Flash Flood Warning	LOX	Los Angeles	3 hr
Mar 7, 4:35 PM PST	Flash Flood Warning Considerable damage threat	LOX	Los Angeles	87 min
Mar 7, 5:06 PM PST	Flash Flood Warning	LOX	Los Angeles	114 min
Mar 7, 5:14 PM PST	Flash Flood Warning Considerable damage threat	SGX	San Bernardino	91 min
Mar 29, 11:43 PM PDT	Flash Flood Warning	LOX	Santa Barbara	3 hr
Mar 30, 12:23 AM PDT	Flash Flood Warning	LOX	Santa Barbara	4 hr
Mar 30, 3:58 AM PDT	Flash Flood Warning	LOX	Los Angeles	4 hr
Mar 30, 9:33 AM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	117 min
Mar 30, 8:13 PM PDT	Flash Flood Warning Considerable damage threat	LOX	Santa Barbara	47 min
Mar 31, 3:25 PM PDT	Flash Flood Warning Considerable damage threat	LOX	Ventura	80 min
Apr 23, 2:31 PM PDT	Flash Flood Warning	EKA	Trinity	119 min
Jun 13, 3:47 PM PDT	Flash Flood Warning	REV	Alpine, Mono	103 min
Jun 13, 3:49 PM PDT	Flash Flood Warning	REV	Alpine, Mono	3 hr
Jun 23, 3:29 PM PDT	Flash Flood Warning	LOX	Los Angeles, Ventura	5 hr
Jul 13, 4:09 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Inyo	3 hr
Jul 13, 4:10 PM PDT	Flash Flood Warning	SGX	San Diego	112 min
Jul 13, 5:01 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Imperial	53 min
Jul 14, 1:50 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 14, 1:56 PM PDT	Flash Flood Warning Considerable damage threat	PSR	San Bernardino	3 hr
Jul 14, 2:07 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	3 hr
Jul 14, 2:51 PM PDT	Flash Flood Warning Considerable damage threat	SGX	Riverside	3 hr
Jul 14, 2:52 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 14, 3:06 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside, San Bernardino	3 hr
Jul 14, 4:41 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Bernardino	3 hr
Jul 14, 5:08 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 14, 7:11 PM PDT	Flash Flood Warning	HNX	Kern	107 min
Jul 15, 2:11 PM PDT	Flash Flood Warning Considerable damage threat	SGX	Riverside	3 hr
Jul 15, 2:35 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	4 hr
Jul 15, 3:08 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	3 hr
Jul 15, 3:15 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	3 hr
Jul 15, 3:24 PM PDT	Flash Flood Warning	STO	Tuolumne	88 min
Jul 15, 3:31 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 15, 3:55 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside, San Bernardino	3 hr
Jul 15, 4:18 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	3 hr
Jul 15, 5:39 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 15, 7:06 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 18, 5:34 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 20, 3:39 PM PDT	Flash Flood Warning	STO	El Dorado	3 hr
Jul 22, 2:40 PM PDT	Flash Flood Warning	REV	Plumas, Sierra	3 hr
Jul 22, 2:47 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 22, 3:08 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Bernardino	3 hr
Jul 22, 6:25 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Inyo	3 hr
Jul 22, 10:15 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 22, 10:19 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Inyo	3 hr
Jul 23, 12:04 AM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 23, 12:51 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 23, 12:56 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside, San Bernardino	3 hr
Jul 23, 1:39 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	4 hr
Jul 23, 3:35 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	2 hr
Jul 23, 6:04 PM PDT	Flash Flood Warning	HNX	Mariposa, Tuolumne	116 min
Jul 24, 2:22 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Inyo	3 hr
Jul 24, 2:25 PM PDT	Flash Flood Warning	REV	Mono	4 hr
Jul 24, 2:55 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Jul 24, 3:48 PM PDT	Flash Flood Warning	HNX	Mariposa, Tuolumne	3 hr
Jul 24, 3:49 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	3 hr
Jul 24, 3:52 PM PDT	Flash Flood Warning	HNX	Mariposa, Tuolumne	3 hr
Jul 24, 4:05 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Inyo	3 hr
Jul 24, 4:51 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Inyo	3 hr
Aug 1, 4:39 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	3 hr
Aug 1, 6:01 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	3 hr
Aug 3, 5:20 PM PDT	Flash Flood Warning	REV	Plumas, Sierra	3 hr
Aug 10, 3:08 PM PDT	Flash Flood Warning	SGX	Riverside	3 hr
Aug 11, 2:53 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	3 hr
Aug 11, 4:05 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Imperial	3 hr
Aug 11, 4:11 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	2 hr
Aug 11, 4:23 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Imperial	3 hr
Aug 21, 5:21 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Sep 7, 2:58 PM PDT	Flash Flood Warning Considerable damage threat	VEF	San Bernardino	3 hr
Sep 8, 1:40 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Bernardino	3 hr
Sep 8, 2:13 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Bernardino	3 hr
Sep 8, 2:43 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Bernardino	3 hr
Sep 8, 2:54 PM PDT	Flash Flood Warning Considerable damage threat	SGX	Riverside, San Bernardino	3 hr
Sep 8, 3:01 PM PDT	Flash Flood Warning Considerable damage threat	SGX	Riverside	3 hr
Sep 8, 3:28 PM PDT	Flash Flood Warning Considerable damage threat	SGX	Riverside, San Bernardino	3 hr
Sep 8, 3:54 PM PDT	Flash Flood Warning Considerable damage threat	SGX	Riverside	3 hr
Sep 8, 5:08 PM PDT	Flash Flood Warning Considerable damage threat	SGX	Riverside	3 hr
Sep 15, 8:48 PM PDT	Flash Flood Warning Considerable damage threat	STO	Butte, Tehama	5 hr
Sep 18, 6:37 PM PDT	Flash Flood Warning Considerable damage threat	STO	Butte, Tehama	4 hr
Sep 19, 4:10 PM PDT	Flash Flood Warning Considerable damage threat	LOX	San Luis Obispo, Santa Barbara	3 hr
Sep 19, 7:05 PM PDT	Flash Flood Warning	LOX	San Luis Obispo, Santa Barbara	60 min
Sep 20, 2:15 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	3 hr
Sep 20, 2:17 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Bernardino	64 min
Nov 11, 9:14 AM PST	Flash Flood Warning Considerable damage threat	STO	Tehama	4 hr
Nov 11, 10:06 AM PST	Flash Flood Warning Considerable damage threat	STO	Butte	3 hr
Nov 14, 5:03 PM PST	Flash Flood Warning Considerable damage threat	STO	Tehama	3 hr
Nov 14, 5:03 PM PST	Flash Flood Warning	STO	Butte	5 hr
Nov 22, 12:43 PM PST	Flash Flood Warning Considerable damage threat	MTR	City and County of San Francisco	3 hr
Nov 22, 2:00 PM PST	Flash Flood Warning	MTR	City and County of San Francisco, San Mateo	3 hr
Nov 22, 2:58 PM PST	Flash Flood Warning	MTR	Alameda, Contra Costa	3 hr
Nov 22, 4:49 PM PST	Flash Flood Warning	MTR	Alameda	3 hr
Dec 14, 12:13 PM PST	Flash Flood Warning Considerable damage threat	HNX	Mariposa	77 min
Dec 14, 12:28 PM PST	Flash Flood Warning	HNX	Mariposa	111 min
Dec 24, 2:51 AM PST	Flash Flood Warning	STO	Tehama	3 hr

By county

Every county with at least one alert. A county page lists each alert that covered it.

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record The radar archive 2023 2025

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.