Alert archive / Iowa / Polk County
Weather alerts in Polk County, Iowa, 2018
202 weather alerts in 2018, 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 2018. Tap one for its archive.
- Alerts
- 202
- Warnings
- 66
- Watches
- 41
- Advisories
- 39
- Busiest month
- June56 alerts
- Busiest day
- July 1, 201821 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
2 of 5 tornado warnings covering Polk County in 2018 had a tornado report inside them; 3 of 6 tornado reports fell inside a warning, on average 8 minutes after it went out.
Polk County, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 5 | 2 | 60% | 6 | 50% | 8 min |
| Severe thunderstorm warnings | 32 | 13 | 59% | 28 | 57% | 18 min |
| Flash flood warnings | 6 | 4 | 33% | 17 | 82% | 71 min |
Each office's whole area, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Des Moines, IA: tornado warnings | 72 | 23 | 68% | 69 | 55% | 15 min |
| NWS Des Moines, IA: severe thunderstorm warnings | 308 | 143 | 54% | 427 | 74% | 22 min |
| NWS Des Moines, IA: flash flood warnings | 39 | 20 | 49% | 70 | 74% | 86 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 3, 3:46 AM CST | Wind Chill Advisory | DMX | 30 hr |
| Jan 10, 2:08 PM CST | Winter Weather Advisory | DMX | 28 hr |
| Jan 14, 3:47 AM CST | Wind Chill Advisory | DMX | 56 hr |
| Jan 21, 2:35 PM CST | Winter Weather Advisory | DMX | 33 hr |
| Jan 21, 6:18 PM CST | Dense Fog Advisory | DMX | 6 hr |
| Jan 26, 10:53 AM CST | Wind Advisory | DMX | 5 hr |
| Feb 4, 2:32 PM CST | Winter Weather Advisory | DMX | 28 hr |
| Feb 5, 11:36 AM CST | Mesoscale Discussion | SPC | 6 hr |
| Feb 7, 2:23 PM CST | Winter Weather Advisory | DMX | 40 hr |
| Feb 9, 3:05 PM CST | Winter Weather Advisory | DMX | 16 hr |
| Feb 18, 3:27 AM CST | Wind Advisory | DMX | 11 hr |
| Feb 18, 3:45 AM CST | Winter Storm Watch | DMX | 24 hr |
| Feb 18, 3:45 AM CST | Winter Weather Advisory | DMX | 56 hr |
| Feb 21, 3:42 PM CST | Winter Weather Advisory | DMX | 35 hr |
| Feb 23, 3:24 PM CST | Winter Weather Advisory | DMX | 30 hr |
| Mar 16, 8:47 PM CDT | Special Weather Statement | DMX | 43 min |
| Mar 23, 4:00 AM CDT | Winter Weather Advisory | DMX | 39 hr |
| Mar 30, 3:19 PM CDT | Wind Advisory | DMX | 25 hr |
| Apr 2, 2:00 PM CDT | Winter Weather Advisory | DMX | 35 hr |
| Apr 3, 4:19 AM CDT | Wind Advisory | DMX | 21 hr |
| Apr 7, 3:05 PM CDT | Winter Weather Advisory | DMX | 40 hr |
| Apr 13, 3:22 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Apr 13, 3:54 PM CDT | Winter Weather Advisory | DMX | 48 hr |
| Apr 13, 8:43 PM CDT | Severe Thunderstorm Warning | DMX | 36 min |
| Apr 14, 1:31 AM CDT | Wind Advisory | DMX | 14 hr |
| Apr 17, 3:54 AM CDT | Winter Weather Advisory | DMX | 42 hr |
| Apr 27, 2:42 PM CDT | Red Flag Warning | DMX | 4 hr |
| Apr 30, 3:18 AM CDT | Wind Advisory | DMX | 17 hr |
| May 1, 10:24 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| May 1, 5:47 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 1, 7:55 PM CDT | Mesoscale Discussion | SPC | 95 min |
| May 1, 9:38 PM CDT | Mesoscale Discussion | SPC | 67 min |
| May 3, 2:57 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 3, 5:26 PM CDT | Tornado Warning | DMX | 34 min |
| May 3, 5:39 PM CDT | Severe Thunderstorm Warning | DMX | 25 min |
| May 3, 5:43 PM CDT | Tornado Warning | DMX | 21 min |
| May 3, 5:58 PM CDT | Mesoscale Discussion | SPC | 92 min |
| May 3, 7:25 PM CDT | Tornado Warning | DMX | 35 min |
| May 3, 7:43 PM CDT | Mesoscale Discussion | SPC | 62 min |
| May 3, 9:30 PM CDT | River Flood Watch | DMX | 13 hr |
| May 12, 1:00 AM CDT | Special Weather Statement | DMX | 45 min |
| May 12, 1:04 AM CDT | Mesoscale Discussion | SPC | 116 min |
| May 13, 11:52 AM CDT | Special Weather Statement | DMX | 38 min |
| May 25, 6:57 PM CDT | Severe Thunderstorm Warning | DMX | 48 min |
| May 25, 7:39 PM CDT | Severe Thunderstorm Warning | DMX | 28 min |
| May 27, 3:51 AM CDT | Heat Advisory | DMX | 16 hr |
| May 27, 8:01 PM CDT | Heat Advisory | DMX | 24 hr |
| May 28, 2:31 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 28, 2:50 PM CDT | Severe Thunderstorm Warning | DMX | 40 min |
| May 28, 4:48 PM CDT | Severe Thunderstorm Warning | DMX | 27 min |
| May 29, 1:43 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 29, 3:30 PM CDT | Severe Thunderstorm Warning | DMX | 18 min |
| May 29, 3:54 PM CDT | Mesoscale Discussion | SPC | 96 min |
| May 29, 5:26 PM CDT | Severe Thunderstorm Warning | DMX | 34 min |
| May 29, 5:37 PM CDT | Severe Thunderstorm Warning | DMX | 23 min |
| Jun 6, 2:22 PM CDT | Mesoscale Discussion | SPC | 113 min |
| Jun 6, 3:23 PM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jun 6, 5:19 PM CDT | Severe Thunderstorm Warning | DMX | 41 min |
| Jun 6, 5:25 PM CDT | Severe Thunderstorm Warning | DMX | 35 min |
| Jun 6, 5:36 PM CDT | Severe Thunderstorm Warning | DMX | 39 min |
| Jun 6, 5:57 PM CDT | Severe Thunderstorm Warning | DMX | 63 min |
| Jun 6, 6:07 PM CDT | Severe Thunderstorm Warning | DMX | 53 min |
| Jun 6, 6:20 PM CDT | Mesoscale Discussion | SPC | 85 min |
| Jun 6, 6:39 PM CDT | Severe Thunderstorm Warning | DMX | 81 min |
| Jun 6, 9:53 PM CDT | Severe Thunderstorm Warning | DMX | 22 min |
| Jun 8, 12:51 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Jun 10, 1:23 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 10, 9:43 PM CDT | Special Weather Statement | DMX | 47 min |
| Jun 10, 9:53 PM CDT | Flash Flood Watch | DMX | 10 hr |
| Jun 10, 10:24 PM CDT | Special Weather Statement | DMX | 51 min |
| Jun 11, 7:39 AM CDT | Special Weather Statement | DMX | 3 hr |
| Jun 11, 9:28 PM CDT | Special Weather Statement | DMX | 62 min |
| Jun 11, 10:07 PM CDT | Special Weather Statement | DMX | 53 min |
| Jun 14, 6:36 AM CDT | Special Weather Statement | DMX | 54 min |
| Jun 14, 3:00 PM CDT | Heat Advisory | DMX | 4 days |
| Jun 14, 7:51 PM CDT | River Flood Warning | DMX | 35 hr |
| Jun 18, 3:05 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 18, 3:41 PM CDT | Flash Flood Watch | DMX | 16 hr |
| Jun 18, 5:46 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Jun 18, 8:34 PM CDT | River Flood Watch | DMX | 6 days |
| Jun 19, 10:02 AM CDT | River Flood Watch | DMX | 6 days |
| Jun 19, 8:39 PM CDT | River Flood Warning | DMX | 9 days |
| Jun 19, 8:39 PM CDT | River Flood Warning | DMX | 8 days |
| Jun 20, 4:28 AM CDT | Flash Flood Watch | DMX | 23 hr |
| Jun 20, 10:43 AM CDT | River Flood Watch | DMX | 6 days |
| Jun 20, 10:43 AM CDT | River Flood Watch | DMX | 6 days |
| Jun 20, 10:43 AM CDT | River Flood Watch | DMX | 7 hr |
| Jun 20, 10:43 AM CDT | River Flood Watch | DMX | 10 hr |
| Jun 20, 1:01 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 20, 2:43 PM CDT | Special Weather Statement | DMX | 62 min |
| Jun 20, 3:04 PM CDT | Tornado Watch | SPC | 4 hr |
| Jun 20, 5:20 PM CDT | River Flood Warning | DMX | 3 hr |
| Jun 24, 3:28 PM CDT | Mesoscale Discussion | SPC | 62 min |
| Jun 25, 5:40 PM CDT | Tornado Watch | SPC | 3 hr |
| Jun 25, 7:25 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 25, 7:46 PM CDT | Severe Thunderstorm Warning | DMX | 30 min |
| Jun 25, 8:19 PM CDT | Special Weather Statement | DMX | 56 min |
| Jun 25, 8:37 PM CDT | Special Weather Statement | DMX | 53 min |
| Jun 25, 9:33 PM CDT | Flash Flood Warning | DMX | 6 hr |
| Jun 26, 3:25 AM CDT | Areal Flood Warning | DMX | 6 hr |
| Jun 27, 3:29 PM CDT | Heat Advisory | DMX | 54 hr |
| Jun 28, 8:12 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 28, 10:57 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 28, 3:42 PM CDT | Heat Advisory | DMX | 29 hr |
| Jun 30, 2:59 AM CDT | Flash Flood Watch | DMX | 27 hr |
| Jun 30, 3:12 AM CDT | Heat Advisory | DMX | 16 hr |
| Jun 30, 10:24 AM CDT | River Flood Watch | DMX | 24 hr |
| Jun 30, 10:24 AM CDT | River Flood Watch | DMX | 16 hr |
| Jun 30, 1:39 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 30, 5:02 PM CDT | Severe Thunderstorm Warning | DMX | 29 min |
| Jun 30, 6:47 PM CDT | Severe Thunderstorm Warning | DMX | 43 min |
| Jun 30, 7:05 PM CDT | Severe Thunderstorm Warning | DMX | 40 min |
| Jun 30, 7:24 PM CDT | Severe Thunderstorm Warning | DMX | 36 min |
| Jun 30, 7:33 PM CDT | Flash Flood Warning | DMX | 6 hr |
| Jun 30, 8:02 PM CDT | Flash Flood Warning | DMX | 6 hr |
| Jun 30, 8:16 PM CDT | Flash Flood Warning | DMX | 6 hr |
| Jun 30, 8:50 PM CDT | River Flood Warning | DMX | 36 hr |
| Jun 30, 9:04 PM CDT | Severe Thunderstorm Warning | DMX | 41 min |
| Jun 30, 9:11 PM CDT | Severe Thunderstorm Warning | DMX | 34 min |
| Jun 30, 9:12 PM CDT | River Flood Warning | DMX | 15 hr |
| Jun 30, 9:23 PM CDT | River Flood Warning | DMX | 16 hr |
| Jun 30, 9:37 PM CDT | River Flood Warning | DMX | 9 days |
| Jun 30, 9:58 PM CDT | Severe Thunderstorm Warning | DMX | 47 min |
| Jun 30, 10:47 PM CDT | River Flood Watch | DMX | 7 hr |
| Jun 30, 10:47 PM CDT | River Flood Watch | DMX | 7 hr |
| Jun 30, 11:04 PM CDT | River Flood Warning | DMX | 32 hr |
| Jun 30, 11:05 PM CDT | River Flood Warning | DMX | 38 hr |
| Jun 30, 11:05 PM CDT | River Flood Warning | DMX | 11 hr |
| Jul 1, 1:21 AM CDT | Flash Flood Warning | DMX | 8 hr |
| Jul 1, 4:30 AM CDT | River Flood Warning | DMX | 47 hr |
| Jul 1, 5:51 AM CDT | River Flood Warning | DMX | 40 hr |
| Jul 1, 9:08 AM CDT | Areal Flood Warning | DMX | 12 hr |
| Jul 3, 2:39 PM CDT | Heat Advisory | DMX | 29 hr |
| Jul 10, 11:51 AM CDT | Mesoscale Discussion | SPC | 84 min |
| Jul 10, 3:30 PM CDT | Heat Advisory | DMX | 53 hr |
| Jul 13, 3:48 AM CDT | Flash Flood Watch | DMX | 18 hr |
| Jul 15, 6:08 AM CDT | Dense Fog Advisory | DMX | 3 hr |
| Jul 19, 2:32 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Jul 19, 2:50 PM CDT | Tornado Warning | DMX | 25 min |
| Jul 19, 3:11 PM CDT | Tornado Watch | SPC | 6 hr |
| Jul 25, 9:43 PM CDT | Special Weather Statement | DMX | 62 min |
| Aug 1, 6:52 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 1, 8:16 PM CDT | Severe Thunderstorm Warning | DMX | 44 min |
| Aug 5, 5:41 AM CDT | Special Weather Statement | DMX | 34 min |
| Aug 5, 10:15 AM CDT | Special Weather Statement | DMX | 60 min |
| Aug 5, 9:32 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 25, 3:19 AM CDT | Dense Fog Advisory | DMX | 6 hr |
| Aug 26, 9:53 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 28, 11:50 AM CDT | Special Weather Statement | DMX | 55 min |
| Aug 28, 12:14 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 31, 1:10 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 31, 8:47 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Sep 1, 4:38 AM CDT | Flash Flood Watch | DMX | 24 hr |
| Sep 1, 7:24 AM CDT | Severe Thunderstorm Warning | DMX | 51 min |
| Sep 1, 6:08 PM CDT | Severe Thunderstorm Warning | DMX | 52 min |
| Sep 1, 6:34 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Sep 1, 7:07 PM CDT | Severe Thunderstorm Warning | DMX | 38 min |
| Sep 1, 7:14 PM CDT | Severe Thunderstorm Warning | DMX | 46 min |
| Sep 1, 7:36 PM CDT | Severe Thunderstorm Warning | DMX | 54 min |
| Sep 1, 7:51 PM CDT | Severe Thunderstorm Warning | DMX | 39 min |
| Sep 1, 8:20 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Sep 1, 8:50 PM CDT | Severe Thunderstorm Warning | DMX | 40 min |
| Sep 1, 9:20 PM CDT | Flash Flood Warning | DMX | 6 hr |
| Sep 1, 10:27 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Sep 2, 12:40 AM CDT | River Flood Warning | DMX | 6 hr |
| Sep 2, 9:45 AM CDT | Flash Flood Watch | DMX | 36 hr |
| Sep 2, 2:24 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 3, 5:47 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Sep 4, 3:33 AM CDT | Flash Flood Watch | DMX | 27 hr |
| Sep 4, 3:35 PM CDT | Tornado Watch | SPC | 7 hr |
| Sep 4, 6:28 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 18, 10:09 AM CDT | Special Weather Statement | DMX | 81 min |
| Sep 18, 11:25 AM CDT | Special Weather Statement | DMX | 65 min |
| Sep 25, 9:27 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 25, 10:28 AM CDT | Special Weather Statement | DMX | 62 min |
| Sep 25, 11:05 AM CDT | Special Weather Statement | DMX | 55 min |
| Oct 3, 12:07 PM CDT | Wind Advisory | DMX | 13 hr |
| Oct 3, 3:06 PM CDT | River Flood Warning | DMX | 42 hr |
| Oct 5, 2:39 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Oct 6, 9:06 PM CDT | River Flood Watch | DMX | 49 hr |
| Oct 6, 9:06 PM CDT | River Flood Watch | DMX | 8 days |
| Oct 7, 3:52 PM CDT | Flood Watch | DMX | 60 hr |
| Oct 7, 10:05 PM CDT | River Flood Watch | DMX | 37 hr |
| Oct 8, 7:03 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Oct 8, 10:26 PM CDT | River Flood Warning | DMX | 7 days |
| Oct 8, 10:26 PM CDT | River Flood Warning | DMX | 7 days |
| Oct 9, 2:49 AM CDT | River Flood Warning | DMX | 3 days |
| Oct 9, 11:33 AM CDT | River Flood Warning | DMX | 6 days |
| Oct 9, 1:46 PM CDT | Tornado Watch | SPC | 7 hr |
| Oct 9, 3:53 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 9, 4:47 PM CDT | River Flood Watch | DMX | 29 hr |
| Oct 9, 6:30 PM CDT | Tornado Warning | DMX | 30 min |
| Oct 13, 3:23 PM CDT | Freeze Watch | DMX | 23 hr |
| Oct 14, 3:45 AM CDT | Freeze Warning | DMX | 30 hr |
| Nov 23, 3:30 AM CST | Winter Storm Watch | DMX | 24 hr |
| Nov 24, 3:40 AM CST | Winter Weather Advisory | DMX | 36 hr |
| Nov 30, 2:34 AM CST | Dense Fog Advisory | DMX | 7 hr |
| Dec 1, 6:56 AM CST | Wind Advisory | DMX | 7 hr |
| Dec 1, 12:55 PM CST | Dense Fog Advisory | DMX | 16 hr |
| Dec 28, 12:55 AM CST | Winter Weather Advisory | DMX | 11 hr |
| Dec 31, 3:26 AM CST | Winter Weather Advisory | DMX | 20 hr |
| Dec 31, 11:50 AM CST | Mesoscale Discussion | SPC | 6 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 | 32 |
| Tornado Warning | 5 |
| Severe Thunderstorm Watch | 9 |
| Tornado Watch | 5 |
| Mesoscale Discussion | 36 |
| Special Weather Statement | 20 |
| Flooding | |
| Areal Flood Warning | 2 |
| Flash Flood Warning | 6 |
| River Flood Warning | 19 |
| Flash Flood Watch | 8 |
| Flood Watch | 1 |
| River Flood Watch | 15 |
| Winter | |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 16 |
| Heat | |
| Heat Advisory | 8 |
| Cold | |
| Freeze Warning | 1 |
| Freeze Watch | 1 |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| Wind Advisory | 8 |
| Fire | |
| Red Flag Warning | 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 archive20172019
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.