Alert archive / South Dakota / Union County
Weather alerts in Union County, South Dakota, 2016
106 weather alerts in 2016, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Union County and its neighbors
Each county as a circle sized by its count in 2016. Tap one for its archive.
- Alerts
- 106
- Warnings
- 30
- Watches
- 16
- Advisories
- 35
- Busiest month
- June19 alerts
- Busiest day
- June 18, 20165 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Union County, 2016
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 11 | 10 | 9% | 0 | ||
| Flash flood warnings | 6 | 3 | 50% | 0 |
Each office's whole area, 2016
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sioux Falls, SD: tornado warnings | 10 | 1 | 90% | 6 | 17% | 6 min |
| NWS Sioux Falls, SD: severe thunderstorm warnings | 182 | 116 | 36% | 239 | 82% | 17 min |
| NWS Sioux Falls, SD: flash flood warnings | 34 | 13 | 62% | 23 | 100% | 64 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, 9:23 PM CST | Dense Fog Advisory | FSD | 13 hr |
| Jan 7, 7:57 AM CST | Dense Fog Advisory | FSD | 4 hr |
| Jan 7, 12:09 PM CST | Dense Fog Advisory | FSD | 111 min |
| Jan 7, 2:03 PM CST | Dense Fog Advisory | FSD | 88 min |
| Jan 9, 3:45 AM CST | Wind Chill Advisory | FSD | 31 hr |
| Jan 16, 3:32 AM CST | Wind Chill Advisory | FSD | 53 hr |
| Jan 24, 7:39 PM CST | Dense Fog Advisory | FSD | 10 hr |
| Jan 31, 3:23 AM CST | Blizzard Watch | FSD | 35 hr |
| Feb 1, 3:38 AM CST | Blizzard Warning | FSD | 48 hr |
| Feb 2, 7:50 AM CST | Mesoscale Discussion | SPC | 4 hr |
| Feb 3, 3:56 AM CST | Winter Weather Advisory | FSD | 8 hr |
| Feb 5, 10:52 PM CST | Dense Fog Advisory | FSD | 11 hr |
| Feb 6, 3:15 PM CST | Wind Advisory | FSD | 51 hr |
| Feb 7, 10:21 PM CST | Winter Weather Advisory | FSD | 29 hr |
| Feb 15, 8:24 AM CST | Dense Fog Advisory | FSD | 4 hr |
| Feb 18, 2:51 PM CST | High Wind Warning | FSD | 21 hr |
| Feb 18, 2:51 PM CST | Wind Advisory | FSD | 24 hr |
| Feb 19, 4:30 AM CST | Wind Advisory | FSD | 11 hr |
| Feb 22, 5:47 AM CST | Dense Fog Advisory | FSD | 6 hr |
| Mar 13, 6:34 AM CDT | Dense Fog Advisory | FSD | 5 hr |
| Mar 13, 9:58 PM CDT | Dense Fog Advisory | FSD | 14 hr |
| Mar 21, 3:37 PM CDT | Winter Storm Watch | FSD | 37 hr |
| Mar 22, 3:19 PM CDT | Winter Storm Warning | FSD | 40 hr |
| Mar 23, 7:15 PM CDT | Mesoscale Discussion | SPC | 6 hr |
| Apr 5, 4:00 PM CDT | Wind Advisory | FSD | 22 hr |
| Apr 6, 2:53 PM CDT | Wind Advisory | FSD | 27 hr |
| Apr 24, 1:31 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Apr 24, 2:28 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Apr 24, 6:10 PM CDT | Mesoscale Discussion | SPC | 65 min |
| Apr 27, 9:56 AM CDT | River Flood Warning | FSD | 8 days |
| Apr 27, 9:56 AM CDT | River Flood Warning | FSD | 9 days |
| May 9, 2:26 PM CDT | Mesoscale Discussion | SPC | 94 min |
| May 9, 4:26 PM CDT | Severe Thunderstorm Warning | FSD | 34 min |
| May 10, 2:42 PM CDT | Mesoscale Discussion | SPC | 93 min |
| May 23, 1:58 PM CDT | Mesoscale Discussion | SPC | 92 min |
| May 23, 5:22 PM CDT | Severe Thunderstorm Warning | FSD | 23 min |
| May 23, 5:58 PM CDT | Flash Flood Warning | FSD | 4 hr |
| May 25, 8:36 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| May 30, 9:49 AM CDT | River Flood Warning | FSD | 24 hr |
| May 30, 9:49 AM CDT | River Flood Warning | FSD | 6 days |
| Jun 9, 3:07 PM CDT | Heat Advisory | FSD | 54 hr |
| Jun 12, 3:36 AM CDT | Heat Advisory | FSD | 16 hr |
| Jun 14, 11:45 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 14, 12:27 PM CDT | Flash Flood Warning | FSD | 3 hr |
| Jun 14, 12:43 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 17, 11:13 AM CDT | Heat Advisory | FSD | 8 hr |
| Jun 17, 3:06 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 17, 6:13 PM CDT | Mesoscale Discussion | SPC | 92 min |
| Jun 17, 8:44 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Jun 17, 8:57 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Jun 17, 9:53 PM CDT | Severe Thunderstorm Warning | FSD | 52 min |
| Jun 17, 10:41 PM CDT | Severe Thunderstorm Warning | FSD | 49 min |
| Jun 18, 3:14 AM CDT | Heat Advisory | FSD | 41 hr |
| Jun 21, 9:49 PM CDT | Mesoscale Discussion | SPC | 26 min |
| Jun 21, 10:21 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 22, 2:31 AM CDT | Mesoscale Discussion | SPC | 119 min |
| Jun 25, 1:52 PM CDT | Mesoscale Discussion | SPC | 83 min |
| Jun 29, 5:36 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Jun 30, 12:50 AM CDT | Flash Flood Warning | FSD | 3 hr |
| Jul 5, 2:57 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Jul 5, 3:29 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 6, 6:48 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Jul 6, 7:38 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 6, 10:10 PM CDT | Severe Thunderstorm Warning | FSD | 50 min |
| Jul 7, 3:54 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jul 9, 3:07 PM CDT | Heat Advisory | FSD | 24 hr |
| Jul 11, 3:16 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Jul 11, 3:48 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 11, 7:25 PM CDT | Mesoscale Discussion | SPC | 65 min |
| Jul 16, 6:57 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 16, 11:45 PM CDT | Severe Thunderstorm Warning | FSD | 30 min |
| Jul 17, 12:14 AM CDT | Severe Thunderstorm Warning | FSD | 31 min |
| Jul 18, 3:57 AM CDT | Excessive Heat Watch | FSD | 24 hr |
| Jul 19, 4:06 AM CDT | Excessive Heat Warning | FSD | 5 days |
| Aug 9, 2:40 PM CDT | Heat Advisory | FSD | 29 hr |
| Aug 11, 12:37 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 11, 3:26 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 11, 3:55 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 11, 6:17 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Aug 16, 7:32 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Aug 16, 8:36 PM CDT | Severe Thunderstorm Warning | FSD | 11 min |
| Sep 4, 10:40 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Sep 5, 12:47 AM CDT | Severe Thunderstorm Warning | FSD | 43 min |
| Sep 5, 1:10 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 5, 1:27 AM CDT | Severe Thunderstorm Warning | FSD | 48 min |
| Sep 7, 1:45 AM CDT | Flash Flood Warning | FSD | 4 hr |
| Sep 15, 11:34 AM CDT | Flash Flood Warning | FSD | 3 hr |
| Sep 15, 1:58 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Sep 15, 2:11 PM CDT | Flash Flood Warning | FSD | 3 hr |
| Sep 15, 8:11 PM CDT | River Flood Warning | FSD | 5 days |
| Sep 15, 8:11 PM CDT | River Flood Warning | FSD | 5 days |
| Oct 4, 6:08 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 6, 2:43 PM CDT | Frost Advisory | FSD | 18 hr |
| Oct 11, 2:59 PM CDT | Freeze Watch | FSD | 13 hr |
| Oct 12, 3:39 AM CDT | Freeze Warning | FSD | 29 hr |
| Oct 16, 2:15 AM CDT | Dense Fog Advisory | FSD | 10 hr |
| Oct 16, 3:48 PM CDT | Dense Fog Advisory | FSD | 19 hr |
| Nov 17, 3:34 AM CST | Winter Weather Advisory | FSD | 41 hr |
| Dec 9, 11:36 AM CST | Winter Weather Advisory | FSD | 43 hr |
| Dec 15, 11:35 AM CST | Winter Weather Advisory | FSD | 48 hr |
| Dec 16, 4:02 AM CST | Wind Chill Warning | FSD | 56 hr |
| Dec 20, 8:31 PM CST | Wind Advisory | FSD | 21 hr |
| Dec 24, 2:41 PM CST | Dense Fog Advisory | FSD | 13 hr |
| Dec 25, 3:07 PM CST | Wind Advisory | FSD | 27 hr |
| Dec 25, 8:54 PM CST | High Wind Warning | FSD | 18 hr |
| Dec 25, 8:54 PM CST | Wind Advisory | FSD | 21 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 | 11 |
| Severe Thunderstorm Watch | 12 |
| Mesoscale Discussion | 25 |
| Flooding | |
| Flash Flood Warning | 6 |
| River Flood Warning | 6 |
| Winter | |
| Blizzard Warning | 1 |
| Winter Storm Warning | 1 |
| Blizzard Watch | 1 |
| Winter Storm Watch | 1 |
| Winter Weather Advisory | 5 |
| Heat | |
| Excessive Heat Warning | 1 |
| Excessive Heat Watch | 1 |
| Heat Advisory | 6 |
| Cold | |
| Freeze Warning | 1 |
| Wind Chill Warning | 1 |
| Freeze Watch | 1 |
| Frost Advisory | 1 |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| High Wind Warning | 2 |
| Wind Advisory | 8 |
| Fog and smoke | |
| Dense Fog Advisory | 13 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20152017
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.