Alert archive / Iowa / Clayton County
Weather alerts in Clayton County, Iowa, 2009
109 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Clayton County and its neighbors
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Alerts
- 109
- Warnings
- 24
- Watches
- 21
- Advisories
- 33
- Busiest month
- July19 alerts
- Busiest day
- July 24, 200914 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
0 of 3 tornado warnings covering Clayton County in 2009 had a tornado report inside them.
Clayton County, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 3 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 8 | 7 | 13% | 9 | 100% | 41 min |
| Flash flood warnings | 3 | 2 | 33% | 1 | 100% | 154 min |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS La Crosse, WI: tornado warnings | 24 | 7 | 71% | 14 | 71% | 18 min |
| NWS La Crosse, WI: severe thunderstorm warnings | 78 | 50 | 36% | 151 | 85% | 25 min |
| NWS La Crosse, WI: flash flood warnings | 15 | 10 | 33% | 22 | 77% | 131 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 3, 3:48 AM CST | Winter Weather Advisory | ARX | 24 hr |
| Jan 3, 6:16 PM CST | Mesoscale Discussion | SPC | 5 hr |
| Jan 8, 2:37 PM CST | Winter Weather Advisory | ARX | 23 hr |
| Jan 11, 3:35 PM CST | Winter Weather Advisory | ARX | 32 hr |
| Jan 12, 3:41 AM CST | Wind Chill Advisory | ARX | 32 hr |
| Jan 12, 6:27 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Jan 13, 3:38 AM CST | Winter Weather Advisory | ARX | 25 hr |
| Jan 13, 11:38 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Jan 14, 4:17 AM CST | Wind Chill Warning | ARX | 56 hr |
| Jan 23, 3:41 AM CST | Wind Chill Advisory | ARX | 32 hr |
| Feb 2, 3:20 PM CST | Wind Chill Advisory | ARX | 19 hr |
| Feb 20, 3:37 AM CST | Winter Weather Advisory | ARX | 35 hr |
| Feb 20, 3:34 PM CST | Winter Storm Warning | ARX | 13 hr |
| Feb 24, 3:21 PM CST | Winter Storm Watch | ARX | 36 hr |
| Feb 26, 3:07 AM CST | Winter Weather Advisory | ARX | 21 hr |
| Mar 5, 9:18 PM CST | Dense Fog Advisory | ARX | 7 hr |
| Mar 7, 1:38 PM CST | Areal Flood Advisory | ARX | 6 hr |
| Mar 7, 3:39 PM CST | Flood Watch | ARX | 23 hr |
| Mar 7, 7:31 PM CST | Areal Flood Advisory | ARX | 4 hr |
| Mar 8, 12:58 PM CDT | Mesoscale Discussion | SPC | 4 hr |
| Mar 8, 4:47 PM CDT | Areal Flood Advisory | ARX | 7 hr |
| Mar 10, 4:08 AM CDT | Wind Advisory | ARX | 30 hr |
| Apr 2, 3:15 PM CDT | Winter Storm Watch | ARX | 44 hr |
| Apr 4, 10:53 AM CDT | Winter Storm Warning | ARX | 24 hr |
| Apr 4, 10:53 AM CDT | Winter Weather Advisory | ARX | 29 hr |
| Apr 21, 10:50 AM CDT | Wind Advisory | ARX | 8 hr |
| Apr 24, 3:18 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 24, 4:45 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Apr 24, 7:42 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Apr 24, 9:40 PM CDT | Mesoscale Discussion | SPC | 65 min |
| Apr 26, 3:45 AM CDT | Flash Flood Watch | ARX | 24 hr |
| Apr 26, 5:02 PM CDT | Tornado Watch | SPC | 6 hr |
| Apr 26, 5:14 PM CDT | Mesoscale Discussion | SPC | 61 min |
| Apr 26, 6:14 PM CDT | Mesoscale Discussion | SPC | 61 min |
| Apr 26, 7:11 PM CDT | Flash Flood Warning | ARX | 6 hr |
| Apr 26, 8:21 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Apr 26, 9:15 PM CDT | River Flood Warning | ARX | 24 hr |
| Apr 26, 9:15 PM CDT | River Flood Warning | ARX | 24 hr |
| Apr 27, 1:05 AM CDT | Areal Flood Warning | ARX | 3 hr |
| May 8, 1:05 PM CDT | Mesoscale Discussion | SPC | 85 min |
| May 8, 5:47 PM CDT | Mesoscale Discussion | SPC | 58 min |
| May 8, 6:10 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| May 16, 4:04 AM CDT | Frost Advisory | ARX | 27 hr |
| Jun 17, 7:01 PM CDT | Tornado Watch | SPC | 5 hr |
| Jun 17, 11:07 PM CDT | Mesoscale Discussion | SPC | 53 min |
| Jun 17, 11:53 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 18, 8:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Jun 18, 8:58 PM CDT | Tornado Watch | SPC | 7 hr |
| Jun 18, 11:47 PM CDT | Severe Thunderstorm Warning | ARX | 28 min |
| Jun 18, 11:52 PM CDT | Flash Flood Warning | ARX | 6 hr |
| Jun 22, 3:09 PM CDT | Heat Advisory | ARX | 27 hr |
| Jun 23, 4:47 PM CDT | Severe Thunderstorm Warning | ARX | 43 min |
| Jun 25, 12:14 PM CDT | Mesoscale Discussion | SPC | 61 min |
| Jun 25, 12:48 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 27, 1:19 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jun 27, 2:41 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 9, 11:31 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Jul 10, 1:36 AM CDT | Mesoscale Discussion | SPC | 24 min |
| Jul 10, 3:06 AM CDT | Severe Thunderstorm Warning | ARX | 54 min |
| Jul 24, 9:51 AM CDT | Mesoscale Discussion | SPC | 54 min |
| Jul 24, 10:32 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 24, 12:40 PM CDT | Severe Thunderstorm Warning | ARX | 65 min |
| Jul 24, 12:53 PM CDT | Areal Flood Advisory | ARX | 3 hr |
| Jul 24, 1:12 PM CDT | Tornado Watch | SPC | 4 hr |
| Jul 24, 1:32 PM CDT | Severe Thunderstorm Warning | ARX | 58 min |
| Jul 24, 1:48 PM CDT | Severe Thunderstorm Warning | ARX | 27 min |
| Jul 24, 1:55 PM CDT | Tornado Warning | ARX | 40 min |
| Jul 24, 3:52 PM CDT | Mesoscale Discussion | SPC | 83 min |
| Jul 24, 5:02 PM CDT | Tornado Watch | SPC | 6 hr |
| Jul 24, 5:36 PM CDT | Severe Thunderstorm Warning | ARX | 69 min |
| Jul 24, 5:52 PM CDT | Flash Flood Warning | ARX | 3 hr |
| Jul 24, 6:12 PM CDT | Tornado Warning | ARX | 33 min |
| Jul 24, 6:44 PM CDT | Severe Thunderstorm Warning | ARX | 54 min |
| Jul 24, 7:20 PM CDT | Mesoscale Discussion | SPC | 85 min |
| Jul 27, 2:10 PM CDT | Mesoscale Discussion | SPC | 65 min |
| Aug 2, 11:37 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 8, 1:29 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 9, 9:55 AM CDT | Mesoscale Discussion | SPC | 35 min |
| Aug 9, 10:21 AM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 9, 2:35 PM CDT | Flash Flood Watch | ARX | 12 hr |
| Aug 19, 4:34 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Aug 19, 4:38 PM CDT | Tornado Warning | ARX | 52 min |
| Aug 19, 4:49 PM CDT | Tornado Watch | SPC | 5 hr |
| Aug 19, 7:45 PM CDT | Mesoscale Discussion | SPC | 90 min |
| Aug 20, 1:51 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Sep 10, 6:37 AM CDT | Dense Fog Advisory | ARX | 3 hr |
| Sep 21, 6:06 AM CDT | Dense Fog Advisory | ARX | 4 hr |
| Sep 26, 3:26 PM CDT | Wind Advisory | ARX | 52 hr |
| Sep 29, 4:02 AM CDT | Frost Advisory | ARX | 28 hr |
| Oct 9, 3:59 AM CDT | Freeze Warning | ARX | 29 hr |
| Oct 27, 3:37 AM CDT | Dense Fog Advisory | ARX | 6 hr |
| Nov 20, 9:48 PM CST | Dense Fog Advisory | ARX | 12 hr |
| Dec 6, 3:11 PM CST | Winter Storm Watch | ARX | 25 hr |
| Dec 7, 3:50 PM CST | Blizzard Warning | ARX | 48 hr |
| Dec 7, 3:50 PM CST | Winter Storm Warning | ARX | 22 hr |
| Dec 8, 11:22 AM CST | Mesoscale Discussion | SPC | 5 hr |
| Dec 8, 6:00 PM CST | Mesoscale Discussion | SPC | 5 hr |
| Dec 9, 10:22 AM CST | Mesoscale Discussion | SPC | 4 hr |
| Dec 9, 3:34 PM CST | Wind Chill Advisory | ARX | 19 hr |
| Dec 9, 3:34 PM CST | Winter Weather Advisory | ARX | 8 hr |
| Dec 12, 2:58 PM CST | Freezing Rain Advisory | ARX | 12 hr |
| Dec 13, 3:20 AM CST | Winter Weather Advisory | ARX | 33 hr |
| Dec 14, 3:19 PM CST | Wind Chill Advisory | ARX | 20 hr |
| Dec 21, 2:57 PM CST | Winter Weather Advisory | ARX | 18 hr |
| Dec 21, 3:34 PM CST | Winter Storm Watch | ARX | 36 hr |
| Dec 22, 7:57 PM CST | Freezing Rain Advisory | ARX | 19 hr |
| Dec 23, 3:58 AM CST | Winter Storm Warning | ARX | 48 hr |
| Dec 23, 6:41 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Dec 24, 11:57 AM CST | Winter Weather Advisory | ARX | 27 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20082010
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.