Alert archive / North Dakota / Sioux County
Weather alerts in Sioux County, North Dakota, 2017
55 weather alerts in 2017, 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 2017. Tap one for its archive.
- Alerts
- 55
- Warnings
- 16
- Watches
- 7
- Advisories
- 0
- Busiest month
- July32 alerts
- Busiest day
- July 19, 20175 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 Sioux County in 2017 had a tornado report inside them.
Sioux County, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 1 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 11 | 7 | 36% | 0 | ||
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Bismarck, ND: tornado warnings | 5 | 1 | 80% | 1 | 100% | 2 min |
| NWS Bismarck, ND: severe thunderstorm warnings | 148 | 98 | 34% | 188 | 89% | 25 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 |
|---|---|---|---|
| Feb 21, 6:46 PM CST | Special Weather Statement | BIS | 44 min |
| Apr 18, 12:13 AM CDT | Special Weather Statement | BIS | 32 min |
| Apr 18, 12:42 AM CDT | Special Weather Statement | BIS | 33 min |
| May 28, 3:54 PM CDT | Mesoscale Discussion | SPC | 66 min |
| Jun 2, 6:12 PM CDT | Special Weather Statement | BIS | 48 min |
| Jun 27, 9:54 PM CDT | Severe Thunderstorm Warning | BIS | 43 min |
| Jul 4, 4:36 PM CDT | Special Weather Statement | BIS | 39 min |
| Jul 4, 5:11 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 5, 4:40 PM CDT | Severe Thunderstorm Warning | BIS | 65 min |
| Jul 5, 5:47 PM CDT | Special Weather Statement | BIS | 43 min |
| Jul 5, 5:52 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 5, 5:57 PM CDT | Special Weather Statement | BIS | 33 min |
| Jul 8, 3:13 AM CDT | Fire Weather Watch | BIS | 24 hr |
| Jul 9, 3:41 AM CDT | Red Flag Warning | BIS | 17 hr |
| Jul 14, 2:51 PM CDT | Fire Weather Watch | BIS | 22 hr |
| Jul 14, 8:29 PM CDT | Special Weather Statement | BIS | 31 min |
| Jul 15, 12:52 PM CDT | Red Flag Warning | BIS | 32 hr |
| Jul 18, 2:00 AM CDT | Special Weather Statement | BIS | 30 min |
| Jul 18, 2:31 AM CDT | Special Weather Statement | BIS | 29 min |
| Jul 18, 2:59 AM CDT | Severe Thunderstorm Warning | BIS | 61 min |
| Jul 19, 6:28 AM CDT | Special Weather Statement | BIS | 32 min |
| Jul 19, 6:49 AM CDT | Severe Thunderstorm Warning | BIS | 56 min |
| Jul 19, 7:01 AM CDT | Mesoscale Discussion | SPC | 119 min |
| Jul 19, 7:43 AM CDT | Severe Thunderstorm Warning | BIS | 49 min |
| Jul 19, 10:32 AM CDT | Special Weather Statement | BIS | 28 min |
| Jul 20, 3:32 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Jul 20, 3:50 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 20, 7:17 PM CDT | Severe Thunderstorm Warning | BIS | 58 min |
| Jul 20, 7:31 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Jul 21, 3:44 AM CDT | Fire Weather Watch | BIS | 25 hr |
| Jul 21, 3:07 PM CDT | Severe Thunderstorm Watch | SPC | 10 hr |
| Jul 21, 6:43 PM CDT | Severe Thunderstorm Warning | BIS | 62 min |
| Jul 21, 7:46 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Jul 21, 10:34 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jul 22, 4:22 AM CDT | Red Flag Warning | BIS | 17 hr |
| Jul 25, 6:43 AM CDT | Special Weather Statement | BIS | 47 min |
| Jul 31, 3:43 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 31, 3:51 PM CDT | Severe Thunderstorm Warning | BIS | 38 min |
| Aug 1, 5:05 AM CDT | Special Weather Statement | BIS | 40 min |
| Aug 1, 5:41 AM CDT | Special Weather Statement | BIS | 49 min |
| Aug 1, 5:59 AM CDT | Special Weather Statement | BIS | 46 min |
| Aug 8, 4:22 PM CDT | Severe Thunderstorm Warning | BIS | 53 min |
| Aug 8, 5:13 PM CDT | Special Weather Statement | BIS | 47 min |
| Aug 8, 5:59 PM CDT | Special Weather Statement | BIS | 46 min |
| Aug 8, 6:23 PM CDT | Special Weather Statement | BIS | 22 min |
| Aug 12, 5:46 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Aug 12, 6:25 PM CDT | Severe Thunderstorm Warning | BIS | 65 min |
| Aug 12, 6:53 PM CDT | Tornado Warning | BIS | 37 min |
| Aug 12, 10:05 PM CDT | Special Weather Statement | BIS | 25 min |
| Aug 26, 2:13 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 26, 4:50 PM CDT | Severe Thunderstorm Warning | BIS | 55 min |
| Sep 1, 2:56 PM CDT | Fire Weather Watch | BIS | 24 hr |
| Sep 2, 2:55 PM CDT | Red Flag Warning | BIS | 30 hr |
| Sep 19, 1:51 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Oct 6, 2:19 PM CDT | Fire Weather Watch | BIS | 29 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 |
| Tornado Warning | 1 |
| Severe Thunderstorm Watch | 2 |
| Mesoscale Discussion | 12 |
| Special Weather Statement | 20 |
| Fire | |
| Red Flag Warning | 4 |
| Fire Weather Watch | 5 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20162018
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.