Alert archive / Iowa / Woodbury County
Weather alerts in Woodbury County, Iowa, 2021
90 weather alerts in 2021, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Woodbury County and its neighbors
Each county as a circle sized by its count in 2021. Tap one for its archive.
- Alerts
- 90
- Warnings
- 26
- Watches
- 13
- Advisories
- 34
- Busiest month
- December18 alerts
- Busiest day
- December 15, 202112 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 5 tornado warnings covering Woodbury County in 2021 had a tornado report inside them; 3 of 3 tornado reports fell inside a warning, on average 5 minutes after it went out.
Woodbury County, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 5 | 2 | 60% | 3 | 100% | 5 min |
| Severe thunderstorm warnings | 12 | 10 | 17% | 15 | 93% | 37 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sioux Falls, SD: tornado warnings | 24 | 3 | 88% | 8 | 50% | 10 min |
| NWS Sioux Falls, SD: severe thunderstorm warnings | 176 | 117 | 34% | 292 | 85% | 20 min |
| NWS Sioux Falls, SD: flash flood warnings | 7 | 3 | 57% | 9 | 89% | 51 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 1, 5:56 PM CST | Dense Fog Advisory | FSD | 21 hr |
| Jan 2, 2:53 PM CST | Dense Fog Advisory | FSD | 39 hr |
| Jan 5, 2:26 PM CST | Winter Weather Advisory | FSD | 24 hr |
| Jan 13, 3:35 AM CST | Winter Storm Watch | FSD | 24 hr |
| Jan 13, 3:32 PM CST | High Wind Warning | FSD | 44 hr |
| Jan 14, 3:30 AM CST | Blizzard Warning | FSD | 39 hr |
| Jan 14, 8:44 PM CST | Mesoscale Discussion | SPC | 5 hr |
| Jan 15, 2:19 PM CST | Winter Weather Advisory | FSD | 8 hr |
| Jan 22, 4:05 AM CST | Winter Weather Advisory | FSD | 44 hr |
| Jan 25, 4:05 AM CST | Winter Weather Advisory | FSD | 29 hr |
| Feb 1, 11:39 PM CST | Dense Fog Advisory | FSD | 11 hr |
| Feb 3, 3:15 AM CST | Winter Weather Advisory | FSD | 33 hr |
| Feb 8, 2:31 PM CST | Wind Chill Advisory | FSD | 18 hr |
| Feb 11, 2:45 PM CST | Wind Chill Advisory | FSD | 21 hr |
| Feb 12, 2:09 PM CST | Wind Chill Watch | FSD | 61 hr |
| Feb 12, 2:09 PM CST | Wind Chill Advisory | FSD | 22 hr |
| Feb 13, 3:35 AM CST | Wind Chill Warning | FSD | 3 days |
| Feb 13, 3:35 AM CST | Wind Chill Advisory | FSD | 30 hr |
| Feb 20, 3:29 AM CST | Winter Weather Advisory | FSD | 36 hr |
| Feb 21, 11:24 AM CST | Winter Storm Warning | FSD | 4 hr |
| Mar 10, 1:47 PM CST | Wind Advisory | FSD | 10 hr |
| Mar 13, 3:18 PM CST | Wind Advisory | FSD | 26 hr |
| Mar 14, 4:03 AM CDT | Winter Weather Advisory | FSD | 30 hr |
| Mar 14, 6:20 PM CDT | Mesoscale Discussion | SPC | 6 hr |
| Mar 15, 1:50 AM CDT | Mesoscale Discussion | SPC | 6 hr |
| Mar 21, 3:04 AM CDT | Wind Advisory | FSD | 12 hr |
| Mar 27, 3:31 PM CDT | Fire Weather Watch | FSD | 23 hr |
| Mar 28, 2:40 PM CDT | Wind Advisory | FSD | 30 hr |
| Mar 28, 2:47 PM CDT | Red Flag Warning | FSD | 30 hr |
| Mar 29, 3:18 PM CDT | Red Flag Warning | FSD | 30 hr |
| Apr 2, 10:49 AM CDT | Red Flag Warning | FSD | 9 hr |
| May 1, 3:09 AM CDT | Red Flag Warning | FSD | 16 hr |
| May 10, 3:12 PM CDT | Frost Advisory | FSD | 17 hr |
| May 19, 1:59 AM CDT | Dense Fog Advisory | FSD | 7 hr |
| Jun 10, 3:31 AM CDT | Heat Advisory | FSD | 16 hr |
| Jun 16, 6:26 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 17, 3:00 AM CDT | Heat Advisory | FSD | 16 hr |
| Jun 22, 3:41 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 22, 6:09 PM CDT | Severe Thunderstorm Warning | FSD | 36 min |
| Jun 22, 6:24 PM CDT | Severe Thunderstorm Warning | FSD | 36 min |
| Jun 22, 6:51 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Jun 22, 6:52 PM CDT | Severe Thunderstorm Warning | FSD | 24 min |
| Jun 23, 8:10 PM CDT | Mesoscale Discussion | SPC | 95 min |
| Jun 23, 10:37 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 25, 1:00 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 5, 3:24 AM CDT | Heat Advisory | FSD | 17 hr |
| Jul 6, 2:01 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 8, 9:33 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jul 8, 11:45 PM CDT | Severe Thunderstorm Warning | FSD | 45 min |
| Jul 9, 2:41 AM CDT | Mesoscale Discussion | SPC | 34 min |
| Jul 14, 1:40 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 14, 2:35 PM CDT | Tornado Watch | SPC | 8 hr |
| Jul 26, 3:11 AM CDT | Excessive Heat Watch | FSD | 35 hr |
| Jul 26, 3:11 AM CDT | Heat Advisory | FSD | 42 hr |
| Jul 27, 2:22 PM CDT | Heat Advisory | FSD | 31 hr |
| Aug 5, 9:34 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Aug 6, 12:10 AM CDT | Severe Thunderstorm Warning | FSD | 35 min |
| Aug 20, 1:51 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Aug 20, 3:58 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 20, 6:13 PM CDT | Severe Thunderstorm Warning | FSD | 32 min |
| Aug 20, 6:31 PM CDT | Severe Thunderstorm Warning | FSD | 29 min |
| Aug 24, 3:31 AM CDT | Heat Advisory | FSD | 11 hr |
| Aug 26, 5:34 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Aug 26, 8:03 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 26, 10:45 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 27, 1:25 AM CDT | Severe Thunderstorm Warning | FSD | 50 min |
| Aug 28, 3:57 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Sep 13, 9:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Sep 17, 1:11 AM CDT | Severe Thunderstorm Warning | FSD | 49 min |
| Oct 15, 3:30 AM CDT | Frost Advisory | FSD | 30 hr |
| Nov 4, 4:23 AM CDT | Dense Fog Advisory | FSD | 10 hr |
| Nov 10, 2:54 PM CST | Wind Advisory | FSD | 51 hr |
| Dec 4, 3:11 PM CST | Wind Advisory | FSD | 35 hr |
| Dec 8, 3:31 AM CST | Winter Storm Watch | FSD | 32 hr |
| Dec 9, 11:23 AM CST | Winter Weather Advisory | FSD | 40 hr |
| Dec 14, 4:04 AM CST | High Wind Warning | FSD | 47 hr |
| Dec 15, 2:56 AM CST | Dense Fog Advisory | FSD | 6 hr |
| Dec 15, 12:28 PM CST | Mesoscale Discussion | SPC | 2 hr |
| Dec 15, 1:23 PM CST | Tornado Watch | SPC | 7 hr |
| Dec 15, 3:23 PM CST | Severe Thunderstorm Warning | FSD | 67 min |
| Dec 15, 3:55 PM CST | Mesoscale Discussion | SPC | 95 min |
| Dec 15, 4:00 PM CST | Tornado Warning | FSD | 45 min |
| Dec 15, 4:05 PM CST | Severe Thunderstorm Warning | FSD | 55 min |
| Dec 15, 4:17 PM CST | Tornado Warning | FSD | 28 min |
| Dec 15, 4:26 PM CST | Severe Thunderstorm Warning | FSD | 34 min |
| Dec 15, 4:31 PM CST | Tornado Warning | FSD | 29 min |
| Dec 15, 4:32 PM CST | Tornado Warning | FSD | 28 min |
| Dec 15, 4:42 PM CST | Tornado Warning | FSD | 33 min |
| Dec 15, 9:07 PM CST | Wind Advisory | FSD | 9 hr |
| Dec 26, 1:52 PM CST | Wind Advisory | FSD | 22 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 | 12 |
| Tornado Warning | 5 |
| Severe Thunderstorm Watch | 6 |
| Tornado Watch | 2 |
| Mesoscale Discussion | 17 |
| Winter | |
| Blizzard Warning | 1 |
| Winter Storm Warning | 1 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 8 |
| Heat | |
| Excessive Heat Watch | 1 |
| Heat Advisory | 6 |
| Cold | |
| Wind Chill Warning | 1 |
| Wind Chill Watch | 1 |
| Frost Advisory | 2 |
| Wind Chill Advisory | 4 |
| Wind and dust | |
| High Wind Warning | 2 |
| Wind Advisory | 8 |
| Fire | |
| Red Flag Warning | 4 |
| Fire Weather Watch | 1 |
| Fog and smoke | |
| Dense Fog Advisory | 6 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20202022
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.