Alert archive / Iowa / Sac County
Weather alerts in Sac County, Iowa, 2020
70 weather alerts in 2020, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Sac County and its neighbors
Each county as a circle sized by its count in 2020. Tap one for its archive.
- Alerts
- 70
- Warnings
- 12
- Watches
- 8
- Advisories
- 35
- Busiest month
- January13 alerts
- Busiest day
- June 5, 20204 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Sac County, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 6 | 4 | 33% | 3 | 100% | 12 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Des Moines, IA: tornado warnings | 16 | 2 | 88% | 15 | 13% | 10 min |
| NWS Des Moines, IA: severe thunderstorm warnings | 172 | 91 | 47% | 286 | 86% | 24 min |
| NWS Des Moines, IA: flash flood warnings | 6 | 2 | 67% | 4 | 75% | 34 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 5, 3:09 AM CST | Wind Advisory | DMX | 13 hr |
| Jan 13, 6:16 PM CST | Winter Weather Advisory | DMX | 9 hr |
| Jan 14, 2:21 PM CST | Winter Weather Advisory | DMX | 21 hr |
| Jan 15, 3:10 PM CST | Winter Storm Watch | DMX | 13 hr |
| Jan 16, 3:59 AM CST | Winter Weather Advisory | DMX | 62 hr |
| Jan 16, 2:04 PM CST | Winter Storm Warning | DMX | 52 hr |
| Jan 17, 3:41 AM CST | Blizzard Warning | DMX | 38 hr |
| Jan 17, 6:32 AM CST | Mesoscale Discussion | SPC | 5 hr |
| Jan 18, 2:53 PM CST | Wind Chill Advisory | DMX | 21 hr |
| Jan 19, 2:52 PM CST | Wind Chill Advisory | DMX | 18 hr |
| Jan 21, 3:54 PM CST | Winter Weather Advisory | DMX | 29 hr |
| Jan 22, 3:34 PM CST | Dense Fog Advisory | DMX | 20 hr |
| Jan 26, 2:06 AM CST | Dense Fog Advisory | DMX | 10 hr |
| Feb 11, 3:21 PM CST | Wind Chill Warning | DMX | 45 hr |
| Feb 11, 3:21 PM CST | Wind Chill Advisory | DMX | 67 hr |
| Feb 11, 3:21 PM CST | Winter Weather Advisory | DMX | 33 hr |
| Feb 14, 3:31 AM CST | Wind Advisory | DMX | 20 hr |
| Mar 4, 3:26 PM CST | Wind Advisory | DMX | 30 hr |
| Mar 19, 3:47 AM CDT | Winter Weather Advisory | DMX | 26 hr |
| Mar 28, 2:59 AM CDT | Wind Advisory | DMX | 34 hr |
| Apr 2, 3:44 AM CDT | Winter Weather Advisory | DMX | 36 hr |
| Apr 8, 3:11 PM CDT | Wind Advisory | DMX | 28 hr |
| Apr 10, 3:41 PM CDT | Winter Storm Watch | DMX | 24 hr |
| Apr 11, 3:23 PM CDT | Winter Weather Advisory | DMX | 31 hr |
| Apr 29, 3:27 AM CDT | Wind Advisory | DMX | 16 hr |
| May 8, 3:23 AM CDT | Frost Advisory | DMX | 29 hr |
| May 10, 2:54 AM CDT | Freeze Warning | DMX | 28 hr |
| May 24, 4:13 AM CDT | Mesoscale Discussion | SPC | 62 min |
| Jun 4, 12:59 PM CDT | Mesoscale Discussion | SPC | 61 min |
| Jun 4, 5:14 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Jun 5, 12:55 AM CDT | Severe Thunderstorm Warning | DMX | 50 min |
| Jun 5, 1:02 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 5, 2:02 AM CDT | Severe Thunderstorm Warning | DMX | 43 min |
| Jun 5, 2:45 AM CDT | Severe Thunderstorm Warning | DMX | 45 min |
| Jun 9, 3:46 PM CDT | Wind Advisory | DMX | 15 hr |
| Jun 18, 3:39 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Jun 18, 4:54 PM CDT | Severe Thunderstorm Warning | DMX | 38 min |
| Jun 21, 3:55 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 21, 6:59 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 28, 8:19 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Jul 3, 1:16 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 17, 3:29 AM CDT | Heat Advisory | DMX | 41 hr |
| Jul 25, 2:40 AM CDT | Heat Advisory | DMX | 17 hr |
| Aug 9, 8:58 AM CDT | Special Weather Statement | DMX | 62 min |
| Aug 9, 10:59 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 10, 8:53 AM CDT | Severe Thunderstorm Warning | DMX | 52 min |
| Aug 10, 8:56 AM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 10, 9:46 AM CDT | Severe Thunderstorm Warning | DMX | 44 min |
| Aug 14, 1:57 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 22, 6:57 PM CDT | Mesoscale Discussion | SPC | 93 min |
| Aug 24, 1:30 PM CDT | Heat Advisory | DMX | 6 hr |
| Sep 13, 4:04 AM CDT | Dense Fog Advisory | DMX | 5 hr |
| Oct 1, 3:44 AM CDT | Frost Advisory | DMX | 28 hr |
| Oct 11, 3:52 PM CDT | Mesoscale Discussion | SPC | 83 min |
| Oct 11, 4:54 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Oct 11, 9:02 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Oct 13, 3:26 PM CDT | Fire Weather Watch | DMX | 12 hr |
| Oct 14, 3:43 AM CDT | Red Flag Warning | DMX | 16 hr |
| Oct 24, 3:05 PM CDT | Winter Weather Advisory | DMX | 34 hr |
| Nov 7, 1:49 PM CST | Wind Advisory | DMX | 28 hr |
| Nov 9, 4:36 PM CST | Winter Weather Advisory | DMX | 25 hr |
| Dec 7, 6:01 PM CST | Dense Fog Advisory | DMX | 15 hr |
| Dec 17, 5:05 PM CST | Dense Fog Advisory | DMX | 10 hr |
| Dec 22, 2:36 PM CST | Winter Weather Advisory | DMX | 36 hr |
| Dec 22, 9:01 PM CST | Blizzard Warning | DMX | 30 hr |
| Dec 23, 12:33 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Dec 24, 3:16 AM CST | Wind Chill Advisory | DMX | 9 hr |
| Dec 24, 3:16 AM CST | Wind Chill Advisory | DMX | 30 hr |
| Dec 27, 5:23 PM CST | Winter Storm Watch | DMX | 10 hr |
| Dec 28, 3:24 AM CST | Winter Weather Advisory | DMX | 48 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 | 6 |
| Severe Thunderstorm Watch | 4 |
| Mesoscale Discussion | 14 |
| Special Weather Statement | 1 |
| Winter | |
| Blizzard Warning | 2 |
| Winter Storm Warning | 1 |
| Winter Storm Watch | 3 |
| Winter Weather Advisory | 12 |
| Heat | |
| Heat Advisory | 3 |
| Cold | |
| Freeze Warning | 1 |
| Wind Chill Warning | 1 |
| Frost Advisory | 2 |
| Wind Chill Advisory | 5 |
| Wind and dust | |
| Wind Advisory | 8 |
| Fire | |
| Red Flag Warning | 1 |
| Fire Weather Watch | 1 |
| Fog and smoke | |
| Dense Fog Advisory | 5 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20192021
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.