Alert archive / California / Lassen County

Weather alerts in Lassen County, California, 2020

110 weather alerts in 2020, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Lassen County and its neighbors

Each county as a circle sized by its count in 2020. Tap one for its archive.

Alerts: 110
Warnings: 33
Watches: 23
Advisories: 40
Busiest month: August26 alerts
Busiest day: July 21, 20205 alerts

Over time

By month

Warning verification

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

1 of 1 tornado warnings covering Lassen County in 2020 had a tornado report inside them; 1 of 3 tornado reports fell inside a warning, on average 29 minutes after it went out.

Lassen County, 2020

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	1	1	0%	3	33%	29 min
Severe thunderstorm warnings	11	0	100%	0
Flash flood warnings	2	0	100%	0

Each office's whole area, 2020

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Reno, NV: tornado warnings	1	1	0%	3	33%	29 min
NWS Reno, NV: severe thunderstorm warnings	34	1	97%	8	13%	7 min
NWS Reno, NV: flash flood warnings	21	2	90%	5	60%	53 min
NWS Sacramento, CA: tornado warnings	0			4	0%
NWS Sacramento, CA: severe thunderstorm warnings	5	2	60%	5	60%	9 min
NWS Sacramento, CA: flash flood warnings	0			3	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	Lasted
Jan 8, 3:24 AM PST	Winter Weather Advisory	REV	31 hr
Jan 11, 11:48 AM PST	Winter Weather Advisory	REV	70 hr
Jan 12, 3:40 AM PST	Winter Storm Watch	REV	58 hr
Jan 14, 3:25 AM PST	High Wind Watch	REV	25 hr
Jan 14, 1:33 PM PST	Winter Weather Advisory	REV	62 hr
Jan 15, 4:12 AM PST	Wind Advisory	REV	39 hr
Jan 21, 2:28 AM PST	Wind Advisory	REV	18 hr
Feb 28, 3:35 PM PST	Winter Weather Advisory	REV	48 hr
Mar 11, 1:54 PM PDT	Winter Storm Watch	REV	49 hr
Mar 12, 2:02 PM PDT	Wind Advisory	REV	54 hr
Mar 13, 4:54 AM PDT	Winter Storm Warning	REV	3 days
Mar 13, 4:54 AM PDT	Winter Weather Advisory	REV	6 days
Mar 23, 3:35 PM PDT	Winter Weather Advisory	REV	42 hr
Apr 2, 12:23 PM PDT	Winter Storm Watch	REV	27 hr
Apr 3, 3:32 PM PDT	Winter Storm Warning	REV	68 hr
Apr 5, 9:49 AM PDT	Winter Weather Advisory	REV	26 hr
May 9, 3:04 PM PDT	Wind Advisory	REV	53 hr
May 15, 6:58 AM PDT	Wind Advisory	REV	61 hr
Jun 4, 1:42 PM PDT	Lake Wind Advisory	REV	30 hr
Jun 4, 6:28 PM PDT	Severe Thunderstorm Warning	REV	32 min
Jun 5, 1:15 PM PDT	Lake Wind Advisory	REV	34 hr
Jun 6, 2:57 AM PDT	Freeze Watch	REV	24 hr
Jun 7, 3:01 AM PDT	Freeze Warning	REV	29 hr
Jun 7, 11:33 AM PDT	Special Weather Statement	REV	3 hr
Jun 11, 10:59 AM PDT	Lake Wind Advisory	REV	35 hr
Jun 14, 2:42 PM PDT	Lake Wind Advisory	REV	31 hr
Jun 15, 2:56 PM PDT	Lake Wind Advisory	REV	30 hr
Jun 23, 6:27 PM PDT	Severe Thunderstorm Warning	REV	33 min
Jun 24, 3:19 PM PDT	Special Weather Statement	REV	56 min
Jun 24, 3:47 PM PDT	Flash Flood Warning	REV	118 min
Jun 25, 1:22 PM PDT	Special Weather Statement	REV	5 hr
Jun 26, 2:06 PM PDT	Lake Wind Advisory	REV	54 hr
Jul 2, 5:31 PM PDT	Special Weather Statement	REV	44 min
Jul 4, 9:26 AM PDT	Fire Weather Watch	REV	23 hr
Jul 5, 2:58 AM PDT	Red Flag Warning	REV	42 hr
Jul 5, 1:20 PM PDT	Lake Wind Advisory	REV	32 hr
Jul 13, 1:48 PM PDT	Fire Weather Watch	REV	62 hr
Jul 19, 8:32 AM PDT	Dense Smoke Advisory	REV	3 days
Jul 20, 1:53 PM PDT	Fire Weather Watch	REV	24 hr
Jul 20, 1:53 PM PDT	Red Flag Warning	REV	55 hr
Jul 20, 7:41 PM PDT	Severe Thunderstorm Warning	REV	34 min
Jul 21, 2:06 PM PDT	Special Weather Statement	REV	99 min
Jul 21, 3:50 PM PDT	Special Weather Statement	REV	115 min
Jul 21, 4:07 PM PDT	Severe Thunderstorm Warning	REV	53 min
Jul 21, 4:39 PM PDT	Severe Thunderstorm Warning	REV	51 min
Jul 21, 6:09 PM PDT	Areal Flood Advisory	REV	2 hr
Jul 22, 11:33 AM PDT	Mesoscale Discussion	SPC	117 min
Jul 22, 12:59 PM PDT	Special Weather Statement	REV	3 hr
Jul 22, 2:08 PM PDT	Severe Thunderstorm Warning	REV	37 min
Jul 22, 3:24 PM PDT	Flash Flood Warning	REV	3 hr
Jul 25, 5:37 AM PDT	Fire Weather Watch	REV	24 hr
Jul 26, 6:06 AM PDT	Red Flag Warning	REV	39 hr
Jul 26, 6:32 PM PDT	Severe Thunderstorm Warning	REV	58 min
Jul 26, 7:27 PM PDT	Areal Flood Advisory	REV	63 min
Jul 27, 3:21 PM PDT	Severe Thunderstorm Warning	STO	24 min
Jul 27, 3:44 PM PDT	Severe Thunderstorm Warning	STO	31 min
Aug 8, 2:02 PM PDT	Fire Weather Watch	REV	69 hr
Aug 10, 5:27 PM PDT	Special Weather Statement	REV	108 min
Aug 11, 10:40 AM PDT	Red Flag Warning	REV	34 hr
Aug 11, 10:42 AM PDT	Lake Wind Advisory	REV	34 hr
Aug 11, 12:50 PM PDT	Severe Thunderstorm Warning	REV	55 min
Aug 11, 7:40 PM PDT	Special Weather Statement	REV	65 min
Aug 15, 2:14 AM PDT	Dense Smoke Advisory	REV	6 hr
Aug 15, 2:35 PM PDT	Tornado Warning	REV	55 min
Aug 15, 2:59 PM PDT	Fire Weather Watch	REV	13 hr
Aug 16, 3:42 AM PDT	Red Flag Warning	REV	25 hr
Aug 16, 10:47 AM PDT	Dense Smoke Advisory	REV	53 hr
Aug 17, 12:31 PM PDT	Fire Weather Watch	REV	26 hr
Aug 17, 3:09 PM PDT	Special Weather Statement	REV	111 min
Aug 18, 2:23 PM PDT	Red Flag Warning	REV	31 hr
Aug 18, 3:45 PM PDT	Severe Thunderstorm Warning	REV	45 min
Aug 18, 3:49 PM PDT	Lake Wind Advisory	REV	29 hr
Aug 19, 10:28 AM PDT	Dense Smoke Advisory	REV	4 days
Aug 21, 10:36 AM PDT	Fire Weather Watch	REV	59 hr
Aug 22, 6:25 PM PDT	Red Flag Warning	REV	41 hr
Aug 23, 9:23 PM PDT	Red Flag Warning	REV	33 hr
Aug 24, 1:36 AM PDT	Special Weather Statement	REV	3 hr
Aug 24, 3:48 PM PDT	Fire Weather Watch	REV	14 hr
Aug 25, 6:10 AM PDT	Red Flag Warning	REV	14 hr
Aug 25, 3:00 PM PDT	Special Weather Statement	REV	2 hr
Aug 26, 5:44 PM PDT	Special Weather Statement	REV	106 min
Aug 27, 9:52 PM PDT	Dense Smoke Advisory	REV	63 hr
Sep 3, 11:29 AM PDT	Heat Advisory	REV	3 days
Sep 5, 1:44 PM PDT	Fire Weather Watch	REV	42 hr
Sep 6, 8:14 AM PDT	Red Flag Warning	REV	60 hr
Sep 7, 2:21 PM PDT	Blowing Dust Advisory	REV	24 hr
Sep 10, 2:06 AM PDT	Dense Smoke Advisory	REV	3 days
Sep 12, 11:00 AM PDT	Fire Weather Watch	REV	33 hr
Sep 13, 11:34 AM PDT	Dense Smoke Advisory	REV	23 hr
Sep 13, 7:51 PM PDT	Red Flag Warning	REV	24 hr
Sep 14, 2:18 PM PDT	Dense Smoke Advisory	REV	4 days
Sep 15, 11:34 AM PDT	Fire Weather Watch	REV	28 hr
Sep 16, 3:12 PM PDT	Red Flag Warning	REV	53 hr
Sep 16, 3:12 PM PDT	Red Flag Warning	REV	53 hr
Oct 21, 3:26 AM PDT	Freeze Watch	REV	35 hr
Oct 22, 2:35 PM PDT	Fire Weather Watch	REV	24 hr
Oct 23, 2:24 PM PDT	Red Flag Warning	REV	4 days
Nov 6, 3:26 AM PST	Winter Weather Advisory	REV	57 hr
Nov 11, 1:15 PM PST	High Wind Watch	REV	13 hr
Nov 12, 2:31 AM PST	High Wind Warning	REV	46 hr
Nov 15, 11:31 AM PST	Wind Advisory	REV	64 hr
Nov 15, 11:49 AM PST	Winter Weather Advisory	REV	3 days
Nov 16, 11:02 AM PST	High Wind Warning	REV	41 hr
Nov 17, 10:01 AM PST	Flash Flood Watch	REV	18 hr
Dec 11, 4:38 AM PST	Winter Weather Advisory	REV	23 hr
Dec 12, 8:19 AM PST	Winter Weather Advisory	REV	42 hr
Dec 14, 12:56 PM PST	Winter Storm Watch	REV	21 hr
Dec 15, 9:48 AM PST	Winter Weather Advisory	REV	50 hr
Dec 22, 1:03 PM PST	Winter Storm Watch	REV	37 hr
Dec 24, 2:00 AM PST	Winter Weather Advisory	REV	56 hr

By product

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

Product	Alerts
Severe storms
Severe Thunderstorm Warning	11
Tornado Warning	1
Mesoscale Discussion	1
Special Weather Statement	13
Flooding
Flash Flood Warning	2
Flash Flood Watch	1
Areal Flood Advisory	2
Winter
Winter Storm Warning	2
Winter Storm Watch	5
Winter Weather Advisory	13
Heat
Heat Advisory	1
Cold
Freeze Warning	1
Freeze Watch	2
Wind and dust
High Wind Warning	2
High Wind Watch	2
Blowing Dust Advisory	1
Lake Wind Advisory	9
Wind Advisory	6
Fire
Red Flag Warning	14
Fire Weather Watch	13
Fog and smoke
Dense Smoke Advisory	8

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2019 2021

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.