Alert archive / South Dakota / Davison County
Weather alerts in Davison County, South Dakota, 2011
84 weather alerts in 2011, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Davison County and its neighbors
Each county as a circle sized by its count in 2011. Tap one for its archive.
- Alerts
- 84
- Warnings
- 23
- Watches
- 16
- Advisories
- 31
- Busiest month
- June13 alerts
- Busiest day
- May 30, 20116 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Davison County, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 11 | 9 | 18% | 5 | 100% | 16 min |
| Flash flood warnings | 1 | 1 | 0% | 1 | 100% | 148 min |
Each office's whole area, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sioux Falls, SD: tornado warnings | 38 | 10 | 74% | 15 | 73% | 12 min |
| NWS Sioux Falls, SD: severe thunderstorm warnings | 274 | 187 | 32% | 337 | 89% | 19 min |
| NWS Sioux Falls, SD: flash flood warnings | 36 | 26 | 28% | 54 | 91% | 61 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 7, 10:00 AM CST | Wind Advisory | FSD | 6 hr |
| Jan 8, 2:24 PM CST | Winter Weather Advisory | FSD | 64 hr |
| Jan 11, 3:37 AM CST | Wind Chill Advisory | FSD | 8 hr |
| Jan 11, 3:14 PM CST | Wind Chill Advisory | FSD | 19 hr |
| Jan 29, 3:39 PM CST | Winter Weather Advisory | FSD | 3 days |
| Jan 31, 3:17 PM CST | Wind Chill Warning | FSD | 45 hr |
| Feb 7, 3:48 AM CST | Wind Chill Advisory | FSD | 32 hr |
| Feb 8, 2:37 PM CST | Wind Chill Advisory | FSD | 21 hr |
| Feb 12, 2:41 PM CST | Wind Advisory | FSD | 36 hr |
| Feb 17, 10:35 AM CST | Wind Advisory | FSD | 10 hr |
| Feb 18, 4:18 AM CST | Winter Storm Watch | FSD | 35 hr |
| Feb 19, 4:07 AM CST | Winter Storm Warning | FSD | 41 hr |
| Feb 19, 3:37 PM CST | Blizzard Warning | FSD | 30 hr |
| Feb 19, 11:25 PM CST | Mesoscale Discussion | SPC | 5 hr |
| Feb 20, 4:36 AM CST | Mesoscale Discussion | SPC | 4 hr |
| Feb 20, 3:25 PM CST | Winter Weather Advisory | FSD | 12 hr |
| Mar 11, 4:00 AM CST | Wind Advisory | FSD | 32 hr |
| Mar 15, 1:17 PM CDT | River Flood Watch | FSD | 6 days |
| Mar 15, 10:11 PM CDT | River Flood Warning | FSD | 8 days |
| Mar 16, 11:32 AM CDT | River Flood Warning | FSD | 247 days |
| Mar 21, 10:05 PM CDT | Mesoscale Discussion | SPC | 115 min |
| Apr 3, 4:17 AM CDT | Wind Advisory | FSD | 36 hr |
| Apr 9, 6:57 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Apr 9, 7:42 PM CDT | Severe Thunderstorm Warning | FSD | 33 min |
| Apr 9, 7:47 PM CDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Apr 14, 3:39 PM CDT | Winter Weather Advisory | FSD | 30 hr |
| Apr 20, 10:33 AM CDT | River Flood Warning | FSD | 22 hr |
| Apr 21, 3:24 AM CDT | Wind Advisory | FSD | 12 hr |
| Apr 29, 3:12 AM CDT | Wind Advisory | FSD | 16 hr |
| Apr 29, 9:11 PM CDT | Wind Advisory | FSD | 28 hr |
| May 1, 3:55 AM CDT | Wind Advisory | FSD | 13 hr |
| May 15, 3:18 PM CDT | Frost Advisory | FSD | 17 hr |
| May 21, 5:53 PM CDT | Severe Thunderstorm Warning | FSD | 37 min |
| May 23, 9:20 PM CDT | River Flood Warning | FSD | 12 hr |
| May 24, 3:30 PM CDT | Wind Advisory | FSD | 27 hr |
| May 29, 10:58 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 30, 12:53 AM CDT | Severe Thunderstorm Warning | FSD | 37 min |
| May 30, 1:40 PM CDT | Mesoscale Discussion | SPC | 95 min |
| May 30, 2:08 PM CDT | Tornado Watch | SPC | 7 hr |
| May 30, 6:17 PM CDT | Mesoscale Discussion | SPC | 118 min |
| May 30, 6:51 PM CDT | Severe Thunderstorm Warning | FSD | 39 min |
| May 31, 3:48 AM CDT | Wind Advisory | FSD | 15 hr |
| Jun 6, 8:10 PM CDT | Mesoscale Discussion | SPC | 95 min |
| Jun 13, 1:44 PM CDT | Severe Thunderstorm Warning | FSD | 31 min |
| Jun 13, 2:11 PM CDT | Severe Thunderstorm Warning | FSD | 34 min |
| Jun 13, 3:06 PM CDT | Severe Thunderstorm Warning | FSD | 39 min |
| Jun 13, 5:32 PM CDT | Flash Flood Warning | FSD | 4 hr |
| Jun 13, 7:39 PM CDT | River Flood Warning | FSD | 4 hr |
| Jun 16, 3:51 PM CDT | Flash Flood Watch | FSD | 29 hr |
| Jun 19, 3:40 AM CDT | Flash Flood Watch | FSD | 55 hr |
| Jun 20, 6:53 PM CDT | Tornado Watch | SPC | 6 hr |
| Jun 20, 9:02 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Jun 20, 11:22 PM CDT | Areal Flood Warning | FSD | 36 hr |
| Jun 21, 11:40 AM CDT | River Flood Warning | FSD | 7 days |
| Jun 29, 3:18 PM CDT | Heat Advisory | FSD | 28 hr |
| Jun 30, 10:07 PM CDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Jul 1, 12:59 PM CDT | Mesoscale Discussion | SPC | 61 min |
| Jul 4, 11:14 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Jul 4, 11:41 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jul 9, 6:09 PM CDT | Mesoscale Discussion | SPC | 66 min |
| Jul 14, 3:31 PM CDT | Excessive Heat Watch | FSD | 12 hr |
| Jul 15, 3:42 AM CDT | Excessive Heat Warning | FSD | 6 days |
| Jul 22, 3:01 PM CDT | Heat Advisory | FSD | 29 hr |
| Jul 26, 8:17 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 30, 3:33 PM CDT | Heat Advisory | FSD | 52 hr |
| Aug 1, 9:40 PM CDT | Mesoscale Discussion | SPC | 95 min |
| Aug 2, 12:42 AM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 6, 12:27 AM CDT | Severe Thunderstorm Warning | FSD | 33 min |
| Aug 11, 3:05 PM CDT | Tornado Watch | SPC | 5 hr |
| Aug 11, 6:59 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Aug 11, 7:19 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 11, 7:29 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Aug 11, 9:42 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Aug 28, 5:16 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 28, 8:00 AM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 28, 8:24 AM CDT | Severe Thunderstorm Warning | FSD | 51 min |
| Sep 14, 4:02 AM CDT | Frost Advisory | FSD | 28 hr |
| Sep 19, 3:28 PM CDT | Wind Advisory | FSD | 34 hr |
| Oct 4, 3:13 PM CDT | Wind Advisory | FSD | 3 days |
| Nov 4, 3:37 AM CDT | Wind Advisory | FSD | 14 hr |
| Nov 4, 3:37 AM CDT | Wind Advisory | FSD | 47 hr |
| Nov 15, 3:26 AM CST | Wind Advisory | FSD | 14 hr |
| Nov 25, 4:30 AM CST | Wind Advisory | FSD | 41 hr |
| Dec 30, 3:15 PM CST | Wind Advisory | FSD | 57 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 archive20102012
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.