Alert archive / Iowa / Sioux County
Weather alerts in Sioux County, Iowa, 2023
135 weather alerts in 2023, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Sioux County and its neighbors
Each county as a circle sized by its count in 2023. Tap one for its archive.
- Alerts
- 135
- Warnings
- 53
- Watches
- 17
- Advisories
- 42
- Busiest month
- July24 alerts
- Busiest day
- August 5, 20238 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
1 of 3 tornado warnings covering Sioux County in 2023 had a tornado report inside them; 2 of 2 tornado reports fell inside a warning, on average 24 minutes after it went out.
Sioux County, 2023
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 3 | 1 | 67% | 2 | 100% | 24 min |
| Severe thunderstorm warnings | 27 | 19 | 30% | 14 | 93% | 20 min |
| Flash flood warnings | 4 | 2 | 50% | 7 | 100% | 27 min |
Each office's whole area, 2023
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sioux Falls, SD: tornado warnings | 23 | 6 | 74% | 16 | 50% | 13 min |
| NWS Sioux Falls, SD: severe thunderstorm warnings | 228 | 126 | 45% | 282 | 82% | 18 min |
| NWS Sioux Falls, SD: flash flood warnings | 9 | 3 | 67% | 12 | 75% | 47 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, 2:10 PM CST | Ice Storm Warning | FSD | 44 hr |
| Jan 3, 3:04 AM CST | Winter Weather Advisory | FSD | 45 hr |
| Jan 5, 9:55 PM CST | Dense Fog Advisory | FSD | 14 hr |
| Jan 6, 10:05 PM CST | Dense Fog Advisory | FSD | 14 hr |
| Jan 8, 11:54 PM CST | Dense Fog Advisory | FSD | 10 hr |
| Jan 11, 3:18 AM CST | Dense Fog Advisory | FSD | 11 hr |
| Jan 12, 6:49 PM CST | Dense Fog Advisory | FSD | 17 hr |
| Jan 16, 3:03 PM CST | Winter Storm Watch | FSD | 24 hr |
| Jan 17, 3:11 PM CST | Winter Storm Warning | FSD | 42 hr |
| Jan 21, 5:56 PM CST | Dense Fog Advisory | FSD | 18 hr |
| Jan 22, 5:54 PM CST | Dense Fog Advisory | FSD | 12 hr |
| Jan 24, 12:55 AM CST | Dense Fog Advisory | FSD | 8 hr |
| Jan 27, 3:12 AM CST | Winter Storm Warning | FSD | 39 hr |
| Jan 27, 3:12 AM CST | Winter Weather Advisory | FSD | 39 hr |
| Jan 27, 9:51 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Jan 28, 1:41 PM CST | Wind Chill Advisory | FSD | 20 hr |
| Jan 29, 1:48 PM CST | Wind Chill Advisory | FSD | 22 hr |
| Jan 30, 2:28 PM CST | Wind Chill Advisory | FSD | 20 hr |
| Feb 5, 5:26 PM CST | Dense Fog Advisory | FSD | 7 hr |
| Feb 14, 2:44 AM CST | Wind Advisory | FSD | 27 hr |
| Feb 19, 2:50 PM CST | Winter Storm Watch | FSD | 36 hr |
| Feb 21, 2:52 AM CST | Blizzard Warning | FSD | 57 hr |
| Feb 21, 2:52 AM CST | Winter Storm Warning | FSD | 57 hr |
| Feb 22, 11:45 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Feb 23, 2:25 PM CST | Wind Chill Advisory | FSD | 20 hr |
| Mar 7, 3:20 AM CST | Winter Storm Watch | FSD | 28 hr |
| Mar 8, 3:30 AM CST | Winter Weather Advisory | FSD | 45 hr |
| Mar 15, 3:29 AM CDT | Winter Storm Watch | FSD | 12 hr |
| Mar 15, 3:26 PM CDT | Winter Weather Advisory | FSD | 40 hr |
| Mar 16, 7:06 PM CDT | Wind Advisory | FSD | 6 hr |
| Mar 22, 1:04 AM CDT | Dense Fog Advisory | FSD | 4 hr |
| Mar 22, 3:42 AM CDT | River Flood Warning | FSD | 11 hr |
| Mar 23, 12:49 AM CDT | Winter Weather Advisory | FSD | 5 hr |
| Mar 30, 3:01 PM CDT | Winter Weather Advisory | FSD | 38 hr |
| Apr 7, 12:30 PM CDT | Red Flag Warning | FSD | 8 hr |
| Apr 7, 2:50 PM CDT | Fire Weather Watch | FSD | 13 hr |
| Apr 8, 3:46 AM CDT | Red Flag Warning | FSD | 16 hr |
| Apr 9, 5:34 AM CDT | River Flood Warning | FSD | 21 days |
| Apr 10, 3:30 AM CDT | Fire Weather Watch | FSD | 10 hr |
| Apr 10, 4:18 AM CDT | River Flood Warning | FSD | 21 days |
| Apr 10, 1:44 PM CDT | Red Flag Warning | FSD | 31 hr |
| Apr 11, 4:19 PM CDT | Red Flag Warning | FSD | 28 hr |
| Apr 12, 3:05 AM CDT | Fire Weather Watch | FSD | 12 hr |
| Apr 12, 3:16 PM CDT | Red Flag Warning | FSD | 29 hr |
| Apr 15, 2:27 PM CDT | Wind Advisory | FSD | 29 hr |
| Apr 19, 2:45 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Apr 19, 3:47 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Apr 19, 7:47 PM CDT | Severe Thunderstorm Warning | FSD | 43 min |
| Apr 19, 8:09 PM CDT | Severe Thunderstorm Warning | FSD | 36 min |
| Apr 19, 8:39 PM CDT | Severe Thunderstorm Warning | FSD | 28 min |
| Apr 19, 8:41 PM CDT | Severe Thunderstorm Warning | FSD | 25 min |
| Apr 19, 9:04 PM CDT | Severe Thunderstorm Warning | FSD | 41 min |
| Apr 19, 9:11 PM CDT | Severe Thunderstorm Warning | FSD | 34 min |
| Apr 30, 3:25 AM CDT | Wind Advisory | FSD | 17 hr |
| May 1, 2:59 PM CDT | Fire Weather Watch | FSD | 13 hr |
| May 2, 3:37 AM CDT | Red Flag Warning | FSD | 16 hr |
| May 7, 12:15 AM CDT | Dense Fog Advisory | FSD | 6 hr |
| May 8, 3:51 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 11, 12:27 AM CDT | Severe Thunderstorm Warning | FSD | 33 min |
| May 11, 12:44 AM CDT | Severe Thunderstorm Warning | FSD | 23 min |
| May 12, 8:17 PM CDT | Severe Thunderstorm Warning | FSD | 28 min |
| May 13, 12:01 PM CDT | Mesoscale Discussion | SPC | 119 min |
| May 31, 3:40 PM CDT | Flash Flood Warning | FSD | 3 hr |
| May 31, 3:52 PM CDT | Severe Thunderstorm Warning | FSD | 23 min |
| Jun 24, 3:10 AM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Jun 24, 4:03 AM CDT | Severe Thunderstorm Warning | FSD | 42 min |
| Jun 24, 4:37 AM CDT | Mesoscale Discussion | SPC | 83 min |
| Jun 24, 4:45 AM CDT | Severe Thunderstorm Warning | FSD | 45 min |
| Jun 24, 3:01 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Jun 24, 9:37 PM CDT | Mesoscale Discussion | SPC | 83 min |
| Jul 3, 3:48 PM CDT | Mesoscale Discussion | SPC | 117 min |
| Jul 3, 4:38 PM CDT | Severe Thunderstorm Warning | FSD | 52 min |
| Jul 3, 5:09 PM CDT | Tornado Warning | FSD | 22 min |
| Jul 8, 3:27 AM CDT | Dense Fog Advisory | FSD | 5 hr |
| Jul 10, 2:09 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 10, 3:12 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 10, 4:17 PM CDT | Severe Thunderstorm Warning | FSD | 28 min |
| Jul 10, 4:47 PM CDT | Severe Thunderstorm Warning | FSD | 28 min |
| Jul 10, 5:03 PM CDT | Severe Thunderstorm Warning | FSD | 12 min |
| Jul 10, 5:12 PM CDT | Severe Thunderstorm Warning | FSD | 33 min |
| Jul 10, 5:59 PM CDT | Mesoscale Discussion | SPC | 61 min |
| Jul 12, 12:10 AM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 12, 3:58 AM CDT | Severe Thunderstorm Warning | FSD | 47 min |
| Jul 12, 4:21 AM CDT | Severe Thunderstorm Warning | FSD | 39 min |
| Jul 12, 4:29 AM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Jul 12, 4:41 AM CDT | Mesoscale Discussion | SPC | 94 min |
| Jul 12, 4:59 AM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Jul 12, 5:13 AM CDT | Severe Thunderstorm Warning | FSD | 47 min |
| Jul 26, 12:50 AM CDT | Mesoscale Discussion | SPC | 85 min |
| Jul 26, 4:14 AM CDT | Heat Advisory | FSD | 16 hr |
| Jul 26, 2:50 PM CDT | Heat Advisory | FSD | 29 hr |
| Jul 27, 8:55 AM CDT | Excessive Heat Warning | FSD | 11 hr |
| Jul 28, 2:46 AM CDT | Excessive Heat Warning | FSD | 17 hr |
| Jul 28, 3:55 PM CDT | Mesoscale Discussion | SPC | 95 min |
| Aug 3, 3:55 AM CDT | Dense Fog Advisory | FSD | 6 hr |
| Aug 5, 2:09 PM CDT | Tornado Warning | FSD | 36 min |
| Aug 5, 2:10 PM CDT | Mesoscale Discussion | SPC | 95 min |
| Aug 5, 2:39 PM CDT | Tornado Warning | FSD | 36 min |
| Aug 5, 3:01 PM CDT | Tornado Watch | SPC | 7 hr |
| Aug 5, 3:18 PM CDT | Flash Flood Warning | FSD | 4 hr |
| Aug 5, 4:41 PM CDT | Flash Flood Warning | FSD | 3 hr |
| Aug 5, 5:02 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Aug 5, 5:20 PM CDT | Flash Flood Warning | FSD | 3 hr |
| Aug 5, 7:27 PM CDT | Areal Flood Warning | FSD | 3 hr |
| Aug 5, 7:53 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 10, 11:08 PM CDT | Severe Thunderstorm Warning | FSD | 52 min |
| Aug 11, 7:40 PM CDT | Severe Thunderstorm Warning | FSD | 50 min |
| Aug 15, 4:09 AM CDT | Dense Fog Advisory | FSD | 4 hr |
| Aug 18, 2:40 PM CDT | Heat Advisory | FSD | 30 hr |
| Aug 19, 2:45 PM CDT | Excessive Heat Watch | FSD | 24 hr |
| Aug 20, 2:41 PM CDT | Excessive Heat Warning | FSD | 4 days |
| Sep 1, 2:09 PM CDT | Heat Advisory | FSD | 53 hr |
| Sep 15, 6:03 PM CDT | Severe Thunderstorm Warning | FSD | 42 min |
| Sep 15, 6:23 PM CDT | Severe Thunderstorm Warning | FSD | 37 min |
| Sep 23, 2:10 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Sep 27, 4:19 AM CDT | Dense Fog Advisory | FSD | 7 hr |
| Sep 29, 5:14 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 29, 6:20 PM CDT | Severe Thunderstorm Warning | FSD | 25 min |
| Oct 3, 5:03 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Oct 3, 6:56 PM CDT | Mesoscale Discussion | SPC | 94 min |
| Oct 5, 3:08 AM CDT | Freeze Watch | FSD | 24 hr |
| Oct 6, 2:48 AM CDT | Freeze Warning | FSD | 30 hr |
| Oct 9, 3:04 PM CDT | Frost Advisory | FSD | 18 hr |
| Oct 11, 8:50 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 23, 9:27 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Oct 27, 2:54 PM CDT | Winter Weather Advisory | FSD | 34 hr |
| Oct 30, 2:37 PM CDT | Wind Advisory | FSD | 19 hr |
| Nov 8, 2:55 PM CST | Fire Weather Watch | FSD | 24 hr |
| Dec 3, 7:06 PM CST | Dense Fog Advisory | FSD | 16 hr |
| Dec 8, 1:57 PM CST | Wind Advisory | FSD | 28 hr |
| Dec 21, 6:21 PM CST | Dense Fog Advisory | FSD | 18 hr |
| Dec 22, 3:30 PM CST | Dense Fog Advisory | FSD | 22 hr |
| Dec 24, 2:22 PM CST | Winter Weather Advisory | FSD | 46 hr |
| Dec 25, 7:00 AM CST | Mesoscale Discussion | SPC | 6 hr |
| Dec 28, 4:11 AM CST | Dense Fog Advisory | FSD | 4 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 archive20222024
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.