Alert archive / North Dakota / Sioux County
Weather alerts in Sioux County, North Dakota, 2018
90 weather alerts in 2018, 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 2018. Tap one for its archive.
- Alerts
- 90
- Warnings
- 24
- Watches
- 15
- Advisories
- 1
- Busiest month
- June39 alerts
- Busiest day
- June 1, 201810 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Sioux County, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 21 | 11 | 48% | 6 | 67% | 33 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Bismarck, ND: tornado warnings | 24 | 5 | 79% | 22 | 64% | 9 min |
| NWS Bismarck, ND: severe thunderstorm warnings | 275 | 164 | 40% | 315 | 90% | 28 min |
| NWS Bismarck, ND: flash flood warnings | 7 | 4 | 43% | 7 | 71% | 119 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 |
|---|---|---|---|
| Apr 28, 3:40 AM CDT | Red Flag Warning | BIS | 17 hr |
| May 4, 4:01 AM CDT | Red Flag Warning | BIS | 15 hr |
| May 17, 3:26 PM CDT | Severe Thunderstorm Warning | BIS | 64 min |
| May 17, 4:03 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 17, 5:27 PM CDT | Severe Thunderstorm Warning | BIS | 36 min |
| May 17, 5:54 PM CDT | Mesoscale Discussion | SPC | 66 min |
| May 22, 5:16 PM CDT | Special Weather Statement | BIS | 29 min |
| May 22, 5:47 PM CDT | Severe Thunderstorm Warning | BIS | 58 min |
| May 22, 5:56 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 22, 5:59 PM CDT | Special Weather Statement | BIS | 31 min |
| May 22, 6:11 PM CDT | Special Weather Statement | BIS | 34 min |
| May 31, 3:17 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 31, 7:00 PM CDT | Mesoscale Discussion | SPC | 90 min |
| May 31, 9:18 PM CDT | Mesoscale Discussion | SPC | 57 min |
| May 31, 9:40 PM CDT | Special Weather Statement | BIS | 50 min |
| May 31, 10:23 PM CDT | Special Weather Statement | BIS | 52 min |
| May 31, 11:33 PM CDT | Special Weather Statement | BIS | 42 min |
| Jun 1, 2:03 AM CDT | Special Weather Statement | BIS | 42 min |
| Jun 1, 2:57 AM CDT | Special Weather Statement | BIS | 48 min |
| Jun 1, 2:13 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 1, 3:30 PM CDT | Tornado Watch | SPC | 6 hr |
| Jun 1, 6:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Jun 5, 6:01 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 5, 9:07 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 5, 9:16 PM CDT | Severe Thunderstorm Warning | BIS | 59 min |
| Jun 10, 2:15 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 10, 3:37 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 10, 6:15 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 10, 8:29 PM CDT | Severe Thunderstorm Warning | BIS | 46 min |
| Jun 10, 9:02 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Jun 10, 9:18 PM CDT | Special Weather Statement | BIS | 42 min |
| Jun 10, 10:04 PM CDT | Special Weather Statement | BIS | 41 min |
| Jun 14, 3:40 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 14, 6:15 PM CDT | Mesoscale Discussion | SPC | 90 min |
| Jun 15, 2:01 AM CDT | Special Weather Statement | BIS | 29 min |
| Jun 27, 12:12 AM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jun 27, 2:18 AM CDT | Mesoscale Discussion | SPC | 87 min |
| Jun 28, 3:52 AM CDT | Mesoscale Discussion | SPC | 83 min |
| Jun 28, 7:40 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 28, 8:00 AM CDT | Severe Thunderstorm Warning | BIS | 60 min |
| Jun 28, 8:56 AM CDT | Severe Thunderstorm Warning | BIS | 64 min |
| Jun 28, 9:58 AM CDT | Severe Thunderstorm Warning | BIS | 47 min |
| Jun 28, 3:16 PM CDT | Tornado Watch | SPC | 8 hr |
| Jun 28, 6:59 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Jun 28, 9:06 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Jun 28, 10:21 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Jun 28, 10:54 PM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jun 29, 12:17 AM CDT | Severe Thunderstorm Warning | BIS | 58 min |
| Jun 29, 1:14 AM CDT | Severe Thunderstorm Warning | BIS | 61 min |
| Jun 29, 2:02 AM CDT | Mesoscale Discussion | SPC | 118 min |
| Jun 29, 5:57 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Jul 2, 5:23 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 2, 7:36 PM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 2, 9:50 PM CDT | Mesoscale Discussion | SPC | 115 min |
| Jul 3, 1:59 AM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 3, 3:15 AM CDT | Severe Thunderstorm Warning | BIS | 60 min |
| Jul 3, 4:12 AM CDT | Severe Thunderstorm Warning | BIS | 63 min |
| Jul 3, 4:15 AM CDT | Mesoscale Discussion | SPC | 90 min |
| Jul 3, 5:03 AM CDT | Severe Thunderstorm Warning | BIS | 57 min |
| Jul 3, 9:39 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 3, 10:55 PM CDT | Severe Thunderstorm Warning | BIS | 65 min |
| Jul 3, 11:32 PM CDT | Areal Flood Advisory | BIS | 6 hr |
| Jul 3, 11:49 PM CDT | Severe Thunderstorm Warning | BIS | 56 min |
| Jul 7, 8:55 PM CDT | Mesoscale Discussion | SPC | 65 min |
| Jul 7, 9:41 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 7, 11:44 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 8, 12:08 AM CDT | Severe Thunderstorm Warning | BIS | 67 min |
| Jul 14, 7:45 PM CDT | Severe Thunderstorm Warning | BIS | 60 min |
| Jul 19, 3:43 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 19, 6:56 PM CDT | Severe Thunderstorm Warning | BIS | 64 min |
| Jul 19, 7:09 PM CDT | Severe Thunderstorm Warning | BIS | 66 min |
| Jul 19, 8:22 PM CDT | Special Weather Statement | BIS | 53 min |
| Jul 22, 1:55 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 4, 12:49 AM CDT | Special Weather Statement | BIS | 71 min |
| Aug 4, 3:42 PM CDT | Mesoscale Discussion | SPC | 93 min |
| Aug 4, 5:55 PM CDT | Special Weather Statement | BIS | 50 min |
| Aug 4, 7:17 PM CDT | Special Weather Statement | BIS | 43 min |
| Aug 10, 3:26 PM CDT | Fire Weather Watch | BIS | 23 hr |
| Aug 11, 2:18 PM CDT | Red Flag Warning | BIS | 31 hr |
| Aug 18, 9:20 PM CDT | Special Weather Statement | BIS | 40 min |
| Aug 18, 9:49 PM CDT | Special Weather Statement | BIS | 41 min |
| Aug 18, 10:28 PM CDT | Special Weather Statement | BIS | 47 min |
| Aug 23, 6:37 PM CDT | Severe Thunderstorm Warning | BIS | 53 min |
| Aug 23, 7:36 PM CDT | Severe Thunderstorm Warning | BIS | 38 min |
| Aug 23, 8:29 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Aug 26, 5:42 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Sep 1, 10:39 PM CDT | Special Weather Statement | BIS | 51 min |
| Sep 1, 11:18 PM CDT | Special Weather Statement | ABR | 42 min |
| Sep 3, 5:44 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Sep 3, 8:14 PM CDT | Mesoscale Discussion | SPC | 2 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 | 21 |
| Severe Thunderstorm Watch | 12 |
| Tornado Watch | 2 |
| Mesoscale Discussion | 30 |
| Special Weather Statement | 20 |
| Flooding | |
| Areal Flood Advisory | 1 |
| Fire | |
| Red Flag Warning | 3 |
| Fire Weather Watch | 1 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20172019
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.