Alert archive / Iowa / Polk County
Weather alerts in Polk County, Iowa, 2017
114 weather alerts in 2017, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Polk County and its neighbors
Each county as a circle sized by its count in 2017. Tap one for its archive.
- Alerts
- 114
- Warnings
- 27
- Watches
- 18
- Advisories
- 28
- Busiest month
- June20 alerts
- Busiest day
- May 17, 201710 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Polk County, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 20 | 13 | 35% | 36 | 97% | 23 min |
| 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 Des Moines, IA: tornado warnings | 25 | 10 | 60% | 18 | 89% | 9 min |
| NWS Des Moines, IA: severe thunderstorm warnings | 275 | 154 | 44% | 522 | 83% | 21 min |
| NWS Des Moines, IA: flash flood warnings | 9 | 6 | 33% | 14 | 86% | 248 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 10, 4:16 AM CST | Winter Weather Advisory | DMX | 14 hr |
| Jan 10, 9:48 AM CST | Wind Advisory | DMX | 8 hr |
| Jan 12, 3:11 PM CST | Winter Storm Watch | DMX | 49 hr |
| Jan 14, 4:13 PM CST | Ice Storm Warning | DMX | 48 hr |
| Jan 14, 4:13 PM CST | Winter Weather Advisory | DMX | 59 hr |
| Jan 16, 3:59 PM CST | Dense Fog Advisory | DMX | 13 hr |
| Jan 18, 9:28 PM CST | Dense Fog Advisory | DMX | 15 hr |
| Jan 19, 3:28 PM CST | Dense Fog Advisory | DMX | 21 hr |
| Jan 20, 3:31 PM CST | Dense Fog Advisory | DMX | 20 hr |
| Jan 21, 3:53 PM CST | Dense Fog Advisory | DMX | 20 hr |
| Feb 7, 3:48 PM CST | Winter Weather Advisory | DMX | 20 hr |
| Feb 23, 4:31 AM CST | Winter Weather Advisory | DMX | 43 hr |
| Feb 23, 9:48 PM CST | Mesoscale Discussion | SPC | 2 hr |
| Mar 6, 4:25 AM CST | Wind Advisory | DMX | 24 hr |
| Mar 6, 1:08 PM CST | Mesoscale Discussion | SPC | 3 hr |
| Mar 6, 1:54 PM CST | Tornado Watch | SPC | 8 hr |
| Mar 6, 3:28 PM CST | Fire Weather Watch | DMX | 13 hr |
| Mar 6, 3:29 PM CST | Wind Advisory | DMX | 27 hr |
| Mar 6, 3:35 PM CST | Mesoscale Discussion | SPC | 115 min |
| Mar 6, 6:11 PM CST | Mesoscale Discussion | SPC | 2 hr |
| Mar 6, 6:30 PM CST | Severe Thunderstorm Warning | DMX | 45 min |
| Mar 6, 7:07 PM CST | Severe Thunderstorm Warning | DMX | 53 min |
| Mar 6, 7:42 PM CST | Mesoscale Discussion | SPC | 63 min |
| Mar 7, 4:00 AM CST | Red Flag Warning | DMX | 14 hr |
| Mar 12, 4:08 AM CDT | Winter Weather Advisory | DMX | 31 hr |
| Apr 15, 4:01 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Apr 15, 5:05 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Apr 15, 7:22 PM CDT | Mesoscale Discussion | SPC | 53 min |
| Apr 18, 2:08 PM CDT | Flash Flood Watch | DMX | 19 hr |
| Apr 19, 8:57 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Apr 19, 10:06 PM CDT | Mesoscale Discussion | SPC | 54 min |
| May 16, 7:31 PM CDT | Mesoscale Discussion | SPC | 59 min |
| May 16, 8:46 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| May 16, 9:30 PM CDT | Severe Thunderstorm Warning | DMX | 15 min |
| May 16, 11:48 PM CDT | Mesoscale Discussion | SPC | 117 min |
| May 17, 11:39 AM CDT | Mesoscale Discussion | SPC | 66 min |
| May 17, 12:08 PM CDT | Tornado Watch | SPC | 7 hr |
| May 17, 2:25 PM CDT | Mesoscale Discussion | SPC | 65 min |
| May 17, 3:02 PM CDT | Severe Thunderstorm Warning | DMX | 43 min |
| May 17, 3:46 PM CDT | Severe Thunderstorm Warning | DMX | 44 min |
| May 17, 4:17 PM CDT | Severe Thunderstorm Warning | DMX | 43 min |
| May 19, 11:11 AM CDT | River Flood Watch | DMX | 5 days |
| May 19, 11:11 AM CDT | River Flood Watch | DMX | 6 days |
| May 20, 8:35 PM CDT | River Flood Warning | DMX | 5 days |
| May 21, 3:41 AM CDT | River Flood Warning | DMX | 51 hr |
| May 22, 7:46 PM CDT | Special Weather Statement | DMX | 59 min |
| May 27, 4:12 AM CDT | Dense Fog Advisory | DMX | 6 hr |
| May 27, 11:39 AM CDT | Special Weather Statement | DMX | 36 min |
| Jun 14, 9:14 AM CDT | Severe Thunderstorm Warning | DMX | 31 min |
| Jun 15, 5:11 PM CDT | Mesoscale Discussion | SPC | 64 min |
| Jun 15, 6:39 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 15, 9:33 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Jun 15, 9:36 PM CDT | Severe Thunderstorm Warning | DMX | 39 min |
| Jun 15, 10:50 PM CDT | Severe Thunderstorm Warning | DMX | 25 min |
| Jun 15, 11:07 PM CDT | Severe Thunderstorm Warning | DMX | 23 min |
| Jun 16, 7:52 PM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jun 22, 9:09 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 22, 9:49 PM CDT | Severe Thunderstorm Warning | DMX | 41 min |
| Jun 22, 10:44 PM CDT | Severe Thunderstorm Warning | DMX | 46 min |
| Jun 22, 11:08 PM CDT | Severe Thunderstorm Warning | DMX | 37 min |
| Jun 28, 3:41 AM CDT | Severe Thunderstorm Warning | DMX | 23 min |
| Jun 28, 2:14 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 28, 2:53 PM CDT | Tornado Watch | SPC | 9 hr |
| Jun 28, 4:49 PM CDT | Severe Thunderstorm Warning | DMX | 41 min |
| Jun 28, 5:11 PM CDT | Severe Thunderstorm Warning | DMX | 49 min |
| Jun 28, 5:24 PM CDT | Severe Thunderstorm Warning | DMX | 24 min |
| Jun 28, 5:29 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Jun 28, 5:52 PM CDT | Severe Thunderstorm Warning | DMX | 2 min |
| Jul 3, 1:48 PM CDT | Special Weather Statement | DMX | 57 min |
| Jul 10, 1:49 AM CDT | Mesoscale Discussion | SPC | 116 min |
| Jul 10, 2:43 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 11, 1:54 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 11, 3:34 AM CDT | Special Weather Statement | DMX | 26 min |
| Jul 11, 4:15 AM CDT | Special Weather Statement | DMX | 15 min |
| Jul 11, 4:21 AM CDT | Heat Advisory | DMX | 16 hr |
| Jul 11, 3:35 PM CDT | Heat Advisory | DMX | 26 hr |
| Jul 12, 3:33 PM CDT | Mesoscale Discussion | SPC | 87 min |
| Jul 17, 2:58 PM CDT | Excessive Heat Watch | DMX | 24 hr |
| Jul 18, 2:58 PM CDT | Excessive Heat Warning | DMX | 4 days |
| Jul 18, 2:58 PM CDT | Heat Advisory | DMX | 4 days |
| Jul 20, 9:19 PM CDT | Severe Thunderstorm Warning | DMX | 56 min |
| Jul 21, 1:32 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 21, 4:52 PM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 21, 6:28 PM CDT | Mesoscale Discussion | SPC | 92 min |
| Jul 21, 8:35 PM CDT | Mesoscale Discussion | SPC | 115 min |
| Jul 21, 11:23 PM CDT | Mesoscale Discussion | SPC | 67 min |
| Jul 26, 3:37 AM CDT | Flash Flood Watch | DMX | 17 hr |
| Aug 18, 4:51 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 18, 6:58 PM CDT | Mesoscale Discussion | SPC | 62 min |
| Aug 18, 9:00 PM CDT | Mesoscale Discussion | SPC | 60 min |
| Aug 20, 11:14 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Aug 21, 6:04 PM CDT | Special Weather Statement | DMX | 41 min |
| Aug 26, 1:35 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 18, 9:56 PM CDT | Dense Fog Advisory | DMX | 12 hr |
| Sep 22, 10:20 AM CDT | Heat Advisory | DMX | 9 hr |
| Sep 25, 5:14 PM CDT | Special Weather Statement | DMX | 61 min |
| Sep 25, 6:20 PM CDT | Special Weather Statement | DMX | 85 min |
| Oct 6, 4:07 AM CDT | Flash Flood Watch | DMX | 23 hr |
| Oct 6, 5:36 PM CDT | Special Weather Statement | DMX | 54 min |
| Oct 6, 8:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Oct 6, 9:54 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Oct 21, 2:57 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 21, 7:55 PM CDT | Severe Thunderstorm Warning | DMX | 24 min |
| Oct 22, 3:10 PM CDT | Wind Advisory | DMX | 51 hr |
| Oct 27, 4:39 AM CDT | Freeze Warning | DMX | 29 hr |
| Nov 12, 9:36 PM CST | Dense Fog Advisory | DMX | 14 hr |
| Nov 17, 7:39 PM CST | Dense Fog Advisory | DMX | 4 hr |
| Dec 3, 3:41 PM CST | Wind Advisory | DMX | 39 hr |
| Dec 5, 4:12 AM CST | Wind Advisory | DMX | 12 hr |
| Dec 12, 3:57 PM CST | Wind Advisory | DMX | 26 hr |
| Dec 18, 5:04 AM CST | Dense Fog Advisory | DMX | 4 hr |
| Dec 26, 1:53 PM CST | Wind Chill Advisory | DMX | 20 hr |
| Dec 29, 3:50 PM CST | Wind Chill Warning | DMX | 4 days |
| Dec 29, 3:50 PM CST | Wind Chill Advisory | DMX | 38 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 | 20 |
| Severe Thunderstorm Watch | 7 |
| Tornado Watch | 3 |
| Mesoscale Discussion | 32 |
| Special Weather Statement | 9 |
| Flooding | |
| River Flood Warning | 2 |
| Flash Flood Watch | 3 |
| River Flood Watch | 2 |
| Winter | |
| Ice Storm Warning | 1 |
| Winter Storm Watch | 1 |
| Winter Weather Advisory | 5 |
| Heat | |
| Excessive Heat Warning | 1 |
| Excessive Heat Watch | 1 |
| Heat Advisory | 4 |
| Cold | |
| Freeze Warning | 1 |
| Wind Chill Warning | 1 |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| Wind Advisory | 7 |
| Fire | |
| Red Flag Warning | 1 |
| Fire Weather Watch | 1 |
| Fog and smoke | |
| Dense Fog Advisory | 10 |
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.