Alert archive / California / Lassen County

Weather alerts in Lassen County, California, 2009

84 weather alerts in 2009, 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 2009. Tap one for its archive.

Alerts: 84
Warnings: 27
Watches: 14
Advisories: 28
Busiest month: July14 alerts
Busiest day: August 2, 20094 alerts

Over time

By month

Warning verification

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

Lassen County, 2009

	Warnings	With a report	False alarm ratio
Tornado warnings	0
Severe thunderstorm warnings	15	1	93%
Flash flood warnings	2	0	100%

Each office's whole area, 2009

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Sacramento, CA: tornado warnings	0			1	0%
NWS Sacramento, CA: severe thunderstorm warnings	31	0	100%	3	0%
NWS Sacramento, CA: flash flood warnings	3	1	67%	2	50%	46 min
NWS Reno, NV: severe thunderstorm warnings	50	3	94%	17	47%	16 min
NWS Reno, NV: flash flood warnings	10	0	100%	4	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 1, 2:37 PM PST	Wind Advisory	REV	27 hr
Jan 24, 9:09 PM PST	Winter Weather Advisory	REV	13 hr
Feb 10, 2:09 PM PST	Winter Weather Advisory	REV	38 hr
Feb 12, 2:54 PM PST	Winter Storm Watch	REV	69 hr
Feb 12, 2:54 PM PST	Winter Weather Advisory	REV	37 hr
Feb 14, 3:39 PM PST	Winter Storm Warning	REV	3 days
Feb 25, 2:22 PM PST	Wind Advisory	REV	29 hr
Mar 1, 4:09 AM PST	Wind Advisory	REV	35 hr
Mar 1, 3:14 PM PST	Winter Storm Watch	REV	13 hr
Mar 1, 3:14 PM PST	Winter Weather Advisory	REV	13 hr
Mar 2, 4:06 AM PST	Winter Storm Warning	REV	54 hr
Mar 14, 4:41 AM PDT	High Wind Watch	REV	34 hr
Mar 15, 2:38 PM PDT	Wind Advisory	REV	29 hr
Mar 21, 4:12 AM PDT	Winter Weather Advisory	REV	31 hr
Apr 2, 3:31 PM PDT	Winter Weather Advisory	REV	17 hr
Apr 7, 4:47 AM PDT	Winter Weather Advisory	REV	30 hr
May 4, 11:44 AM PDT	Areal Flood Advisory	REV	24 hr
May 24, 5:29 PM PDT	Severe Thunderstorm Warning	REV	46 min
May 27, 4:12 PM PDT	Severe Thunderstorm Warning	REV	33 min
May 28, 3:57 PM PDT	Severe Thunderstorm Warning	REV	48 min
May 28, 4:32 PM PDT	Flash Flood Warning	REV	118 min
May 28, 4:56 PM PDT	Severe Thunderstorm Warning	REV	21 min
May 28, 5:37 PM PDT	Severe Thunderstorm Warning	STO	44 min
May 31, 6:43 AM PDT	Flash Flood Watch	REV	12 hr
Jun 3, 12:35 PM PDT	Mesoscale Discussion	SPC	85 min
Jun 8, 5:35 PM PDT	Special Weather Statement	REV	40 min
Jun 18, 2:57 PM PDT	Lake Wind Advisory	REV	32 hr
Jun 19, 1:15 PM PDT	Special Weather Statement	REV	60 min
Jun 19, 3:37 PM PDT	Special Weather Statement	REV	53 min
Jun 19, 4:31 PM PDT	Special Weather Statement	REV	59 min
Jun 19, 6:31 PM PDT	Special Weather Statement	REV	59 min
Jun 19, 6:57 PM PDT	Special Weather Statement	REV	33 min
Jun 19, 7:15 PM PDT	Special Weather Statement	REV	45 min
Jul 1, 4:36 PM PDT	Special Weather Statement	REV	24 min
Jul 4, 3:00 PM PDT	Fire Weather Watch	REV	44 hr
Jul 5, 3:29 PM PDT	Fire Weather Watch	REV	47 hr
Jul 6, 10:28 AM PDT	Lake Wind Advisory	REV	37 hr
Jul 6, 10:37 AM PDT	Red Flag Warning	REV	35 hr
Jul 11, 3:06 PM PDT	Lake Wind Advisory	REV	32 hr
Jul 17, 6:33 AM PDT	Fire Weather Watch	REV	23 hr
Jul 28, 4:22 PM PDT	Severe Thunderstorm Warning	STO	29 min
Jul 29, 8:27 PM PDT	Severe Thunderstorm Warning	REV	48 min
Jul 30, 3:21 PM PDT	Special Weather Statement	REV	24 min
Jul 30, 4:53 PM PDT	Severe Thunderstorm Warning	REV	52 min
Jul 30, 5:11 PM PDT	Severe Thunderstorm Warning	REV	49 min
Jul 30, 5:27 PM PDT	Flash Flood Warning	REV	89 min
Jul 30, 6:44 PM PDT	Severe Thunderstorm Warning	REV	46 min
Jul 31, 6:34 PM PDT	Severe Thunderstorm Warning	REV	26 min
Aug 1, 2:46 PM PDT	Special Weather Statement	REV	29 min
Aug 1, 3:34 PM PDT	Mesoscale Discussion	SPC	56 min
Aug 1, 7:41 PM PDT	Special Weather Statement	REV	49 min
Aug 2, 2:37 PM PDT	Fire Weather Watch	REV	25 hr
Aug 2, 2:37 PM PDT	Fire Weather Watch	REV	40 hr
Aug 2, 2:50 PM PDT	Special Weather Statement	REV	25 min
Aug 2, 6:46 PM PDT	Severe Thunderstorm Warning	REV	32 min
Aug 2, 7:00 PM PDT	Severe Thunderstorm Warning	REV	30 min
Aug 2, 8:29 PM PDT	Special Weather Statement	REV	61 min
Aug 4, 6:34 AM PDT	Red Flag Warning	REV	38 hr
Aug 4, 2:48 PM PDT	Lake Wind Advisory	REV	31 hr
Sep 3, 2:34 PM PDT	Fire Weather Watch	REV	18 hr
Sep 4, 8:43 AM PDT	Red Flag Warning	REV	35 hr
Sep 4, 2:43 PM PDT	Lake Wind Advisory	REV	31 hr
Sep 4, 2:43 PM PDT	Lake Wind Advisory	REV	53 hr
Sep 12, 4:08 PM PDT	Severe Thunderstorm Warning	REV	22 min
Sep 26, 2:43 PM PDT	Fire Weather Watch	REV	24 hr
Sep 27, 2:34 PM PDT	Red Flag Warning	REV	53 hr
Oct 13, 3:56 AM PDT	High Wind Warning	REV	23 hr
Oct 13, 4:16 PM PDT	Wind Advisory	REV	11 hr
Nov 4, 2:29 PM PST	Wind Advisory	REV	32 hr
Nov 18, 12:44 PM PST	Winter Storm Watch	REV	23 hr
Nov 19, 11:35 AM PST	High Wind Warning	REV	34 hr
Nov 19, 11:41 AM PST	Winter Storm Warning	REV	31 hr
Nov 26, 2:23 PM PST	Winter Weather Advisory	REV	44 hr
Dec 5, 4:21 AM PST	Winter Storm Watch	REV	24 hr
Dec 6, 4:09 AM PST	Winter Storm Warning	REV	39 hr
Dec 10, 4:46 AM PST	Winter Storm Watch	REV	34 hr
Dec 10, 2:59 PM PST	Winter Weather Advisory	REV	19 hr
Dec 11, 4:26 AM PST	Winter Storm Warning	REV	54 hr
Dec 14, 5:15 AM PST	Freezing Fog Advisory	REV	6 hr
Dec 14, 2:54 PM PST	Freezing Fog Advisory	REV	16 hr
Dec 18, 2:54 PM PST	Freezing Fog Advisory	REV	19 hr
Dec 19, 3:08 PM PST	Freezing Fog Advisory	REV	19 hr
Dec 20, 3:29 PM PST	Winter Weather Advisory	REV	42 hr
Dec 29, 2:52 PM PST	Winter Weather Advisory	REV	19 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	14
Mesoscale Discussion	2
Special Weather Statement	13
Flooding
Flash Flood Warning	2
Flash Flood Watch	1
Areal Flood Advisory	1
Winter
Winter Storm Warning	5
Winter Storm Watch	5
Winter Weather Advisory	11
Wind and dust
High Wind Warning	2
High Wind Watch	1
Lake Wind Advisory	6
Wind Advisory	6
Fire
Red Flag Warning	4
Fire Weather Watch	7
Fog and smoke
Freezing Fog Advisory	4

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2008 2010

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.