Alert archive / Iowa / Clayton County
Weather alerts in Clayton County, Iowa, 2020
108 weather alerts in 2020, 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 2020. Tap one for its archive.
- Alerts
- 108
- Warnings
- 19
- Watches
- 16
- Advisories
- 32
- Busiest month
- June21 alerts
- Busiest day
- September 6, 20207 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 1 tornado warnings covering Clayton County in 2020 had a tornado report inside them.
Clayton County, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 1 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 6 | 3 | 50% | 4 | 0% | |
| Flash flood warnings | 1 | 0 | 100% | 0 |
Each office's whole area, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS La Crosse, WI: tornado warnings | 8 | 3 | 63% | 11 | 55% | 9 min |
| NWS La Crosse, WI: severe thunderstorm warnings | 99 | 48 | 52% | 182 | 70% | 22 min |
| NWS La Crosse, WI: flash flood warnings | 12 | 9 | 25% | 34 | 85% | 127 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, 6:10 PM CST | Winter Weather Advisory | ARX | 6 hr |
| Jan 10, 2:59 AM CST | Winter Weather Advisory | ARX | 24 hr |
| Jan 10, 5:50 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Jan 13, 2:04 PM CST | Winter Weather Advisory | ARX | 16 hr |
| Jan 14, 1:57 PM CST | Winter Weather Advisory | ARX | 22 hr |
| Jan 15, 3:25 PM CST | Winter Storm Watch | ARX | 21 hr |
| Jan 16, 12:42 PM CST | Winter Storm Warning | ARX | 53 hr |
| Jan 18, 2:18 PM CST | Wind Chill Advisory | ARX | 22 hr |
| Feb 8, 3:49 AM CST | Winter Weather Advisory | ARX | 35 hr |
| Feb 12, 4:11 AM CST | Wind Chill Advisory | ARX | 54 hr |
| Feb 16, 3:05 PM CST | Winter Weather Advisory | ARX | 33 hr |
| Feb 17, 3:27 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Feb 23, 2:20 PM CST | Winter Storm Watch | ARX | 13 hr |
| Mar 4, 8:15 PM CST | Wind Advisory | ARX | 28 hr |
| Mar 20, 10:49 AM CDT | River Flood Warning | ARX | 52 hr |
| Mar 28, 3:44 PM CDT | Special Weather Statement | ARX | 46 min |
| Mar 28, 6:42 PM CDT | Mesoscale Discussion | SPC | 93 min |
| Mar 28, 6:52 PM CDT | Tornado Warning | ARX | 53 min |
| Mar 29, 10:02 AM CDT | River Flood Warning | ARX | 20 days |
| Apr 1, 10:09 AM CDT | River Flood Warning | ARX | 15 days |
| Apr 7, 3:31 AM CDT | Dense Fog Advisory | ARX | 6 hr |
| Apr 8, 12:48 AM CDT | Dense Fog Advisory | ARX | 8 hr |
| Apr 9, 2:46 AM CDT | Wind Advisory | ARX | 16 hr |
| Apr 22, 5:14 PM CDT | Special Weather Statement | ARX | 61 min |
| May 7, 9:48 AM CDT | Freeze Watch | ARX | 17 hr |
| May 8, 3:13 AM CDT | Freeze Warning | ARX | 29 hr |
| May 10, 2:51 AM CDT | Freeze Warning | ARX | 29 hr |
| May 11, 3:27 PM CDT | Frost Advisory | ARX | 17 hr |
| May 15, 2:52 AM CDT | Dense Fog Advisory | ARX | 5 hr |
| May 23, 12:33 PM CDT | Tornado Watch | SPC | 8 hr |
| May 23, 2:51 PM CDT | Mesoscale Discussion | SPC | 84 min |
| May 24, 2:00 AM CDT | Dense Fog Advisory | ARX | 7 hr |
| May 26, 6:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| May 28, 3:47 AM CDT | Flash Flood Watch | ARX | 10 hr |
| Jun 2, 4:39 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 2, 5:32 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Jun 2, 8:06 PM CDT | Special Weather Statement | ARX | 54 min |
| Jun 2, 11:46 PM CDT | Special Weather Statement | ARX | 59 min |
| Jun 4, 5:09 PM CDT | Special Weather Statement | ARX | 36 min |
| Jun 4, 5:14 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Jun 4, 10:50 PM CDT | Mesoscale Discussion | SPC | 115 min |
| Jun 5, 1:02 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 8, 3:21 AM CDT | Flash Flood Watch | ARX | 47 hr |
| Jun 9, 7:51 PM CDT | River Flood Warning | ARX | 56 hr |
| Jun 9, 7:51 PM CDT | River Flood Warning | ARX | 61 hr |
| Jun 21, 2:35 PM CDT | Special Weather Statement | ARX | 25 min |
| Jun 21, 2:46 PM CDT | Severe Thunderstorm Warning | ARX | 27 min |
| Jun 21, 9:09 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 22, 10:09 AM CDT | Flash Flood Watch | ARX | 9 hr |
| Jun 26, 3:34 AM CDT | Severe Thunderstorm Warning | ARX | 28 min |
| Jun 26, 9:14 AM CDT | Special Weather Statement | ARX | 31 min |
| Jun 26, 12:38 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 26, 1:38 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 26, 2:40 PM CDT | Special Weather Statement | ARX | 50 min |
| Jun 26, 3:39 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 7, 1:23 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 7, 3:38 PM CDT | Heat Advisory | ARX | 27 hr |
| Jul 7, 3:43 PM CDT | Special Weather Statement | ARX | 32 min |
| Jul 9, 10:24 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 9, 11:05 AM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 9, 2:07 PM CDT | Special Weather Statement | ARX | 53 min |
| Jul 9, 2:29 PM CDT | Severe Thunderstorm Warning | ARX | 61 min |
| Jul 11, 6:05 PM CDT | Special Weather Statement | ARX | 55 min |
| Jul 11, 6:19 PM CDT | Special Weather Statement | ARX | 56 min |
| Jul 11, 6:40 PM CDT | Special Weather Statement | ARX | 65 min |
| Jul 11, 6:55 PM CDT | Special Weather Statement | ARX | 65 min |
| Jul 11, 7:33 PM CDT | Severe Thunderstorm Warning | ARX | 29 min |
| Jul 14, 4:11 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 14, 8:00 PM CDT | Mesoscale Discussion | SPC | 60 min |
| Jul 17, 2:35 AM CDT | Heat Advisory | ARX | 41 hr |
| Jul 18, 8:57 AM CDT | Special Weather Statement | ARX | 63 min |
| Jul 25, 2:44 AM CDT | Heat Advisory | ARX | 17 hr |
| Jul 26, 2:53 AM CDT | Heat Advisory | ARX | 16 hr |
| Aug 9, 9:07 AM CDT | Special Weather Statement | ARX | 68 min |
| Aug 10, 10:42 AM CDT | Mesoscale Discussion | SPC | 93 min |
| Aug 10, 11:26 AM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 10, 11:44 AM CDT | Special Weather Statement | ARX | 46 min |
| Aug 10, 12:04 PM CDT | Severe Thunderstorm Warning | ARX | 41 min |
| Aug 24, 3:21 AM CDT | Heat Advisory | ARX | 16 hr |
| Aug 25, 2:48 AM CDT | Heat Advisory | ARX | 16 hr |
| Aug 26, 2:53 AM CDT | Heat Advisory | ARX | 16 hr |
| Aug 28, 2:56 PM CDT | Mesoscale Discussion | SPC | 64 min |
| Aug 28, 3:16 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Sep 5, 7:53 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 5, 9:34 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Sep 6, 12:10 AM CDT | Special Weather Statement | ARX | 65 min |
| Sep 6, 1:06 AM CDT | Mesoscale Discussion | SPC | 84 min |
| Sep 6, 1:15 AM CDT | Special Weather Statement | ARX | 60 min |
| Sep 6, 2:32 AM CDT | Mesoscale Discussion | SPC | 88 min |
| Sep 6, 2:56 AM CDT | Severe Thunderstorm Warning | ARX | 49 min |
| Oct 1, 3:56 AM CDT | Frost Advisory | ARX | 28 hr |
| Oct 3, 1:44 PM CDT | Frost Advisory | ARX | 18 hr |
| Oct 4, 10:37 AM CDT | Frost Advisory | ARX | 21 hr |
| Oct 12, 3:42 AM CDT | Special Weather Statement | ARX | 48 min |
| Oct 15, 1:30 PM CDT | Freeze Warning | ARX | 18 hr |
| Oct 22, 4:53 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 22, 8:54 PM CDT | Flash Flood Warning | ARX | 3 hr |
| Oct 22, 11:43 PM CDT | Areal Flood Warning | ARX | 7 hr |
| Oct 31, 11:48 PM CDT | Wind Advisory | ARX | 15 hr |
| Nov 14, 2:06 PM CST | Wind Advisory | ARX | 28 hr |
| Nov 23, 2:19 PM CST | Winter Weather Advisory | ARX | 30 hr |
| Nov 24, 7:49 PM CST | Dense Fog Advisory | ARX | 12 hr |
| Dec 11, 3:01 AM CST | Winter Weather Advisory | ARX | 35 hr |
| Dec 21, 3:31 AM CST | Wind Advisory | ARX | 12 hr |
| Dec 28, 3:45 AM CST | Winter Storm Watch | ARX | 11 hr |
| Dec 28, 3:45 AM CST | Winter Weather Advisory | ARX | 53 hr |
| Dec 28, 2:31 PM CST | Winter Storm Warning | ARX | 37 hr |
| Dec 29, 2:17 PM CST | Mesoscale Discussion | SPC | 4 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 | 6 |
| Tornado Warning | 1 |
| Severe Thunderstorm Watch | 8 |
| Tornado Watch | 1 |
| Mesoscale Discussion | 21 |
| Special Weather Statement | 20 |
| Flooding | |
| Areal Flood Warning | 1 |
| Flash Flood Warning | 1 |
| River Flood Warning | 5 |
| Flash Flood Watch | 3 |
| Winter | |
| Winter Storm Warning | 2 |
| Winter Storm Watch | 3 |
| Winter Weather Advisory | 9 |
| Heat | |
| Heat Advisory | 7 |
| Cold | |
| Freeze Warning | 3 |
| Freeze Watch | 1 |
| Frost Advisory | 4 |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| Wind Advisory | 5 |
| Fog and smoke | |
| Dense Fog Advisory | 5 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20192021
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.