Alert archive / South Dakota / Clay County

Weather alerts in Clay County, South Dakota, 2008

142 weather alerts in 2008, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Clay County and its neighbors

Each county as a circle sized by its count in 2008. Tap one for its archive.

Alerts: 142
Warnings: 34
Watches: 25
Advisories: 42
Busiest month: June37 alerts
Busiest day: June 5, 20089 alerts

Over time

By month

Warning verification

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

2 of 3 tornado warnings covering Clay County in 2008 had a tornado report inside them; 2 of 2 tornado reports fell inside a warning, on average 6 minutes after it went out.

Clay County, 2008

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	3	2	33%	2	100%	6 min
Severe thunderstorm warnings	20	7	65%	8	100%	16 min
Flash flood warnings	2	2	0%	0

Each office's whole area, 2008

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Sioux Falls, SD: tornado warnings	55	19	65%	49	90%	14 min
NWS Sioux Falls, SD: severe thunderstorm warnings	296	130	56%	253	82%	19 min
NWS Sioux Falls, SD: flash flood warnings	28	20	29%	44	89%	88 min

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, Central Time. Each opens its own page with the text, the map, the radar and the sounding.

Issued	Product	Office	Lasted
Jan 17, 10:39 AM CST	Wind Chill Advisory	FSD	52 hr
Jan 19, 3:16 PM CST	Snow Advisory	FSD	51 hr
Jan 22, 3:55 PM CST	Blowing Snow Advisory	FSD	19 hr
Jan 28, 3:16 PM CST	Winter Weather Advisory	FSD	21 hr
Jan 28, 7:22 PM CST	Wind Advisory	FSD	11 hr
Jan 29, 4:19 AM CST	Wind Chill Advisory	FSD	29 hr
Feb 3, 3:51 PM CST	Snow Advisory	FSD	20 hr
Feb 3, 9:38 PM CST	Winter Weather Advisory	FSD	17 hr
Feb 8, 3:09 PM CST	Wind Chill Advisory	FSD	49 hr
Feb 8, 3:09 PM CST	Winter Weather Advisory	FSD	24 hr
Feb 10, 9:43 PM CST	Snow Advisory	FSD	29 hr
Feb 11, 12:32 PM CST	Mesoscale Discussion	SPC	5 hr
Feb 14, 1:27 AM CST	Freezing Rain Advisory	FSD	2 hr
Feb 17, 12:25 PM CST	Wind Advisory	FSD	7 hr
Feb 19, 4:00 AM CST	Wind Chill Advisory	FSD	31 hr
Feb 19, 3:34 PM CST	Wind Chill Warning	FSD	20 hr
Feb 24, 3:58 PM CST	Winter Weather Advisory	FSD	26 hr
Mar 2, 3:34 AM CST	Wind Advisory	FSD	14 hr
Mar 17, 4:32 AM CDT	Snow Advisory	FSD	8 hr
Mar 17, 7:25 PM CDT	Dense Fog Advisory	FSD	15 hr
Mar 30, 2:32 PM CDT	Snow Advisory	FSD	28 hr
Mar 31, 2:30 AM CDT	Mesoscale Discussion	SPC	5 hr
Apr 9, 3:47 AM CDT	Winter Storm Watch	FSD	24 hr
Apr 10, 4:10 AM CDT	Blizzard Warning	FSD	32 hr
Apr 10, 4:10 AM CDT	Winter Weather Advisory	FSD	32 hr
Apr 14, 3:53 PM CDT	Wind Advisory	FSD	29 hr
Apr 25, 6:06 AM CDT	Mesoscale Discussion	SPC	6 hr
May 1, 3:28 PM CDT	Mesoscale Discussion	SPC	92 min
May 1, 4:34 PM CDT	Tornado Watch	SPC	5 hr
May 1, 6:33 PM CDT	Mesoscale Discussion	SPC	57 min
May 2, 3:49 PM CDT	Wind Advisory	FSD	12 hr
May 6, 10:56 AM CDT	Mesoscale Discussion	SPC	94 min
May 6, 12:03 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
May 6, 2:22 PM CDT	Mesoscale Discussion	SPC	113 min
May 6, 2:54 PM CDT	Severe Thunderstorm Warning	FSD	36 min
May 6, 4:24 PM CDT	Severe Thunderstorm Warning	FSD	36 min
May 10, 3:22 AM CDT	Wind Advisory	FSD	25 hr
May 17, 12:16 PM CDT	Wind Advisory	FSD	8 hr
May 19, 12:48 PM CDT	Wind Advisory	FSD	7 hr
May 24, 2:17 PM CDT	Mesoscale Discussion	SPC	118 min
May 24, 9:01 PM CDT	Mesoscale Discussion	SPC	59 min
May 28, 11:41 PM CDT	Mesoscale Discussion	SPC	94 min
May 29, 3:28 AM CDT	Flash Flood Watch	FSD	24 hr
May 29, 5:32 AM CDT	Mesoscale Discussion	SPC	118 min
May 29, 5:07 PM CDT	Mesoscale Discussion	SPC	23 min
May 29, 5:26 PM CDT	Tornado Watch	SPC	6 hr
May 29, 7:04 PM CDT	Severe Thunderstorm Warning	FSD	41 min
May 29, 7:07 PM CDT	Tornado Warning	FSD	23 min
May 29, 7:09 PM CDT	Tornado Warning	FSD	36 min
May 29, 7:28 PM CDT	Tornado Warning	FSD	22 min
May 29, 7:33 PM CDT	Severe Thunderstorm Warning	FSD	42 min
May 29, 8:02 PM CDT	Severe Thunderstorm Warning	FSD	19 min
Jun 3, 1:57 AM CDT	Severe Thunderstorm Warning	FSD	20 min
Jun 3, 1:57 AM CDT	Severe Thunderstorm Watch	SPC	3 hr
Jun 3, 4:12 AM CDT	Mesoscale Discussion	SPC	2 hr
Jun 3, 9:36 AM CDT	River Flood Warning	FSD	11 days
Jun 4, 3:00 PM CDT	Flash Flood Watch	FSD	12 hr
Jun 5, 10:11 AM CDT	Mesoscale Discussion	SPC	94 min
Jun 5, 10:35 AM CDT	Flash Flood Watch	FSD	11 hr
Jun 5, 10:55 AM CDT	Tornado Watch PDS	SPC	8 hr
Jun 5, 11:30 AM CDT	Severe Thunderstorm Warning	FSD	30 min
Jun 5, 12:18 PM CDT	Flash Flood Warning	FSD	6 hr
Jun 5, 12:26 PM CDT	Severe Thunderstorm Warning	FSD	34 min
Jun 5, 12:59 PM CDT	Severe Thunderstorm Warning	FSD	31 min
Jun 5, 5:10 PM CDT	Mesoscale Discussion	SPC	95 min
Jun 5, 5:50 PM CDT	Tornado Watch PDS	SPC	7 hr
Jun 5, 7:32 PM CDT	Areal Flood Warning	FSD	12 hr
Jun 7, 3:14 AM CDT	Flash Flood Watch	FSD	27 hr
Jun 7, 10:15 PM CDT	Mesoscale Discussion	SPC	90 min
Jun 7, 10:57 PM CDT	Severe Thunderstorm Warning	FSD	20 min
Jun 7, 11:01 PM CDT	Mesoscale Discussion	SPC	59 min
Jun 7, 11:11 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jun 11, 10:22 AM CDT	Wind Advisory	FSD	5 hr
Jun 11, 2:03 PM CDT	Mesoscale Discussion	SPC	117 min
Jun 19, 5:31 PM CDT	Severe Thunderstorm Warning	FSD	44 min
Jun 19, 6:11 PM CDT	Mesoscale Discussion	SPC	64 min
Jun 19, 6:17 PM CDT	Severe Thunderstorm Warning	FSD	43 min
Jun 19, 6:50 PM CDT	Severe Thunderstorm Warning	FSD	25 min
Jun 21, 3:05 PM CDT	Mesoscale Discussion	SPC	85 min
Jun 25, 1:36 AM CDT	Mesoscale Discussion	SPC	84 min
Jun 26, 5:32 AM CDT	Severe Thunderstorm Warning	FSD	43 min
Jun 26, 6:38 AM CDT	Severe Thunderstorm Watch	SPC	6 hr
Jun 26, 7:51 AM CDT	Mesoscale Discussion	SPC	84 min
Jun 26, 9:53 AM CDT	Mesoscale Discussion	SPC	97 min
Jun 26, 10:55 AM CDT	Severe Thunderstorm Warning	FSD	35 min
Jun 26, 3:06 PM CDT	Flash Flood Watch	FSD	12 hr
Jun 26, 9:46 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jun 27, 6:58 PM CDT	Severe Thunderstorm Warning	FSD	19 min
Jun 28, 3:06 AM CDT	Wind Advisory	FSD	18 hr
Jul 6, 2:36 PM CDT	Mesoscale Discussion	SPC	114 min
Jul 6, 3:05 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 7, 1:36 PM CDT	Mesoscale Discussion	SPC	114 min
Jul 11, 3:13 PM CDT	Mesoscale Discussion	SPC	92 min
Jul 15, 2:37 PM CDT	Mesoscale Discussion	SPC	83 min
Jul 19, 1:09 PM CDT	Mesoscale Discussion	SPC	2 hr
Jul 19, 2:28 PM CDT	Tornado Watch	SPC	8 hr
Jul 19, 4:05 PM CDT	Severe Thunderstorm Warning	FSD	40 min
Jul 19, 4:47 PM CDT	Severe Thunderstorm Warning	FSD	43 min
Jul 20, 8:58 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 20, 11:11 PM CDT	Severe Thunderstorm Warning	FSD	49 min
Jul 20, 11:36 PM CDT	Severe Thunderstorm Warning	FSD	39 min
Jul 21, 12:16 AM CDT	Flash Flood Warning	FSD	3 hr
Jul 21, 4:01 AM CDT	Mesoscale Discussion	SPC	89 min
Jul 23, 10:45 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 24, 1:46 AM CDT	Mesoscale Discussion	SPC	89 min
Jul 26, 11:34 PM CDT	Severe Thunderstorm Watch	SPC	8 hr
Jul 27, 7:15 AM CDT	Mesoscale Discussion	SPC	90 min
Jul 27, 1:02 PM CDT	Mesoscale Discussion	SPC	118 min
Jul 27, 2:29 PM CDT	Severe Thunderstorm Watch	SPC	8 hr
Aug 2, 10:13 PM CDT	Mesoscale Discussion	SPC	62 min
Aug 2, 11:13 PM CDT	Severe Thunderstorm Watch	SPC	4 hr
Aug 13, 4:37 PM CDT	Mesoscale Discussion	SPC	53 min
Aug 27, 4:48 PM CDT	Mesoscale Discussion	SPC	117 min
Sep 1, 3:54 AM CDT	Wind Advisory	FSD	15 hr
Sep 24, 11:04 PM CDT	Mesoscale Discussion	SPC	86 min
Sep 28, 4:59 PM CDT	Severe Thunderstorm Watch	SPC	5 hr
Sep 28, 7:04 PM CDT	Mesoscale Discussion	SPC	116 min
Sep 28, 9:22 PM CDT	Mesoscale Discussion	SPC	53 min
Oct 1, 9:40 AM CDT	Frost Advisory	FSD	23 hr
Oct 12, 3:56 AM CDT	Wind Advisory	FSD	15 hr
Oct 13, 3:33 PM CDT	Freeze Warning	FSD	17 hr
Oct 15, 3:05 PM CDT	Freeze Warning	FSD	18 hr
Oct 25, 1:41 PM CDT	High Wind Watch	FSD	14 hr
Oct 26, 3:49 AM CDT	High Wind Warning	FSD	16 hr
Nov 5, 2:51 PM CST	Mesoscale Discussion	SPC	114 min
Nov 6, 3:30 AM CST	Wind Advisory	FSD	39 hr
Nov 6, 3:45 AM CST	Winter Weather Advisory	FSD	38 hr
Nov 10, 11:06 AM CST	Winter Weather Advisory	FSD	27 hr
Nov 10, 7:19 PM CST	Mesoscale Discussion	SPC	4 hr
Nov 11, 9:24 AM CST	Winter Weather Advisory	FSD	3 hr
Nov 12, 2:50 AM CST	Dense Fog Advisory	FSD	7 hr
Dec 8, 4:34 AM CST	Winter Weather Advisory	FSD	23 hr
Dec 13, 4:01 PM CST	Winter Weather Advisory	FSD	32 hr
Dec 14, 3:50 PM CST	Wind Chill Advisory	FSD	24 hr
Dec 17, 8:44 PM CST	Winter Weather Advisory	FSD	33 hr
Dec 18, 3:39 PM CST	Blizzard Watch	FSD	24 hr
Dec 18, 6:37 PM CST	Mesoscale Discussion	SPC	5 hr
Dec 19, 4:25 AM CST	Winter Weather Advisory	FSD	32 hr
Dec 19, 4:08 PM CST	Blizzard Warning	FSD	47 hr
Dec 20, 3:59 PM CST	Wind Chill Warning	FSD	29 hr
Dec 26, 9:06 AM CST	Dense Fog Advisory	FSD	4 hr
Dec 29, 3:04 PM CST	Wind Advisory	FSD	20 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	20
Tornado Warning	3
Severe Thunderstorm Watch	12
Tornado Watch	5
Mesoscale Discussion	41
Flooding
Areal Flood Warning	1
Flash Flood Warning	2
River Flood Warning	1
Flash Flood Watch	5
Winter
Blizzard Warning	2
Blizzard Watch	1
Winter Storm Watch	1
Blowing Snow Advisory	1
Freezing Rain Advisory	1
Snow Advisory	5
Winter Weather Advisory	12
Cold
Freeze Warning	2
Wind Chill Warning	2
Frost Advisory	1
Wind Chill Advisory	5
Wind and dust
High Wind Warning	1
High Wind Watch	1
Wind Advisory	14
Fog and smoke
Dense Fog Advisory	3

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2007 2009

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.