Alert archive / Minnesota / Rock County
Weather alerts in Rock County, Minnesota, 2009
91 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Rock County and its neighbors
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Alerts
- 91
- Warnings
- 9
- Watches
- 19
- Advisories
- 32
- Busiest month
- June16 alerts
- Busiest day
- July 7, 20095 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Rock County, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 6 | 2 | 67% | 1 | 100% | 5 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sioux Falls, SD: tornado warnings | 49 | 16 | 67% | 23 | 78% | 21 min |
| NWS Sioux Falls, SD: severe thunderstorm warnings | 232 | 172 | 26% | 374 | 81% | 19 min |
| NWS Sioux Falls, SD: flash flood warnings | 25 | 18 | 28% | 34 | 88% | 49 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 2, 3:55 PM CST | Winter Weather Advisory | FSD | 29 hr |
| Jan 3, 8:56 PM CST | Wind Chill Advisory | FSD | 13 hr |
| Jan 8, 4:02 AM CST | Winter Weather Advisory | FSD | 24 hr |
| Jan 11, 4:33 AM CST | Blizzard Watch | FSD | 24 hr |
| Jan 11, 2:50 PM CST | Winter Weather Advisory | FSD | 30 hr |
| Jan 12, 10:56 AM CST | Mesoscale Discussion | SPC | 6 hr |
| Jan 12, 6:40 PM CST | Wind Chill Advisory | FSD | 11 hr |
| Jan 13, 3:17 PM CST | Wind Chill Advisory | FSD | 33 hr |
| Jan 13, 6:12 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Jan 23, 3:33 AM CST | Wind Chill Advisory | FSD | 32 hr |
| Feb 2, 3:00 PM CST | Wind Chill Advisory | FSD | 19 hr |
| Feb 24, 4:11 PM CST | Winter Storm Watch | FSD | 23 hr |
| Feb 25, 11:07 AM CST | Winter Weather Advisory | FSD | 29 hr |
| Feb 26, 6:33 AM CST | Mesoscale Discussion | SPC | 5 hr |
| Mar 6, 3:39 PM CST | Winter Weather Advisory | FSD | 44 hr |
| Mar 9, 3:44 AM CDT | Dense Fog Advisory | FSD | 6 hr |
| Mar 9, 10:01 AM CDT | Dense Fog Advisory | FSD | 119 min |
| Mar 9, 4:05 PM CDT | Winter Weather Advisory | FSD | 12 hr |
| Mar 9, 6:46 PM CDT | Winter Weather Advisory | FSD | 4 hr |
| Mar 10, 2:51 PM CDT | Wind Chill Advisory | FSD | 21 hr |
| Mar 22, 3:44 AM CDT | Wind Advisory | FSD | 44 hr |
| Mar 23, 6:04 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Mar 23, 6:44 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Mar 28, 3:59 PM CDT | Winter Storm Watch | FSD | 36 hr |
| Mar 30, 4:08 AM CDT | Winter Weather Advisory | FSD | 41 hr |
| Mar 30, 11:16 AM CDT | Wind Advisory | FSD | 8 hr |
| Mar 31, 1:26 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Apr 2, 3:24 PM CDT | Winter Storm Watch | FSD | 30 hr |
| Apr 3, 10:40 AM CDT | Blizzard Warning | FSD | 41 hr |
| Apr 3, 4:05 PM CDT | Blizzard Watch | FSD | 6 hr |
| Apr 4, 9:11 PM CDT | Mesoscale Discussion | SPC | 4 hr |
| Apr 20, 10:33 AM CDT | Wind Advisory | FSD | 8 hr |
| Apr 23, 3:29 AM CDT | Wind Advisory | FSD | 16 hr |
| May 12, 3:49 PM CDT | Wind Advisory | FSD | 30 hr |
| May 12, 8:42 PM CDT | Mesoscale Discussion | SPC | 93 min |
| May 15, 1:17 PM CDT | Mesoscale Discussion | SPC | 58 min |
| May 19, 3:18 PM CDT | Wind Advisory | FSD | 28 hr |
| Jun 7, 11:16 AM CDT | Mesoscale Discussion | SPC | 119 min |
| Jun 16, 8:47 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Jun 17, 3:59 AM CDT | Dense Fog Advisory | FSD | 5 hr |
| Jun 17, 5:43 PM CDT | Mesoscale Discussion | SPC | 92 min |
| Jun 17, 6:21 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 18, 6:52 PM CDT | Mesoscale Discussion | SPC | 113 min |
| Jun 19, 4:20 PM CDT | Severe Thunderstorm Warning | FSD | 40 min |
| Jun 21, 3:17 PM CDT | Tornado Watch | SPC | 8 hr |
| Jun 23, 7:24 AM CDT | Mesoscale Discussion | SPC | 96 min |
| Jun 23, 8:01 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 23, 10:05 AM CDT | Severe Thunderstorm Warning | FSD | 25 min |
| Jun 23, 11:31 AM CDT | Mesoscale Discussion | SPC | 89 min |
| Jun 24, 6:16 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 24, 8:49 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Jun 26, 10:13 PM CDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Jun 26, 11:46 PM CDT | Mesoscale Discussion | SPC | 59 min |
| Jul 6, 2:58 PM CDT | Mesoscale Discussion | SPC | 32 min |
| Jul 7, 1:47 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Jul 7, 2:13 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 7, 3:56 PM CDT | Mesoscale Discussion | SPC | 34 min |
| Jul 7, 6:12 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Jul 7, 6:33 PM CDT | Mesoscale Discussion | SPC | 27 min |
| Jul 9, 3:07 AM CDT | Mesoscale Discussion | SPC | 83 min |
| Jul 9, 3:41 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 9, 12:07 PM CDT | Flash Flood Watch | FSD | 21 hr |
| Jul 9, 6:34 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Jul 9, 7:02 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 9, 7:44 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Jul 9, 11:31 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Jul 14, 1:42 PM CDT | Mesoscale Discussion | SPC | 93 min |
| Jul 14, 2:40 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 21, 12:20 PM CDT | Mesoscale Discussion | SPC | 55 min |
| Jul 31, 7:13 PM CDT | Severe Thunderstorm Warning | FSD | 47 min |
| Jul 31, 7:43 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 2, 8:32 PM CDT | Mesoscale Discussion | SPC | 28 min |
| Aug 2, 8:41 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 8, 12:16 PM CDT | Mesoscale Discussion | SPC | 29 min |
| Aug 8, 12:47 PM CDT | Tornado Watch | SPC | 5 hr |
| Aug 8, 3:27 PM CDT | Mesoscale Discussion | SPC | 33 min |
| Aug 19, 5:32 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Sep 26, 2:26 PM CDT | Wind Advisory | FSD | 30 hr |
| Sep 28, 3:20 PM CDT | Frost Advisory | FSD | 18 hr |
| Oct 8, 3:43 AM CDT | Freeze Warning | FSD | 28 hr |
| Oct 11, 4:01 AM CDT | Winter Weather Advisory | FSD | 30 hr |
| Dec 7, 3:39 AM CST | Winter Weather Advisory | FSD | 49 hr |
| Dec 8, 1:33 PM CST | Blizzard Warning | FSD | 25 hr |
| Dec 8, 9:38 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Dec 9, 4:10 AM CST | Wind Chill Advisory | FSD | 30 hr |
| Dec 21, 2:02 PM CST | Winter Storm Watch | FSD | 24 hr |
| Dec 21, 4:39 PM CST | Freezing Rain Advisory | FSD | 3 hr |
| Dec 21, 9:01 PM CST | Winter Weather Advisory | FSD | 5 hr |
| Dec 22, 4:30 AM CST | Winter Storm Warning | FSD | 4 days |
| Dec 23, 4:48 AM CST | Winter Weather Advisory | FSD | 13 hr |
| Dec 26, 3:56 AM CST | Winter Weather Advisory | FSD | 20 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 | 5 |
| Severe Thunderstorm Watch | 10 |
| Tornado Watch | 2 |
| Mesoscale Discussion | 31 |
| Flooding | |
| Flash Flood Watch | 1 |
| Winter | |
| Blizzard Warning | 2 |
| Winter Storm Warning | 1 |
| Blizzard Watch | 2 |
| Winter Storm Watch | 4 |
| Freezing Rain Advisory | 1 |
| Winter Weather Advisory | 13 |
| Cold | |
| Freeze Warning | 1 |
| Frost Advisory | 1 |
| Wind Chill Advisory | 7 |
| Wind and dust | |
| Wind Advisory | 7 |
| Fog and smoke | |
| Dense Fog Advisory | 3 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20082010
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.