Alert archive / North Dakota / Williams County
Weather alerts in Williams County, North Dakota, 2009
113 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Williams County and its neighbors
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Alerts
- 113
- Warnings
- 37
- Watches
- 20
- Advisories
- 40
- Busiest month
- July16 alerts
- Busiest day
- August 24, 200910 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
0 of 3 tornado warnings covering Williams County in 2009 had a tornado report inside them.
Williams County, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 3 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 14 | 7 | 50% | 5 | 100% | 29 min |
| Flash flood warnings | 1 | 1 | 0% | 1 | 100% | 24 min |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Bismarck, ND: tornado warnings | 56 | 11 | 80% | 19 | 79% | 13 min |
| NWS Bismarck, ND: severe thunderstorm warnings | 180 | 61 | 66% | 124 | 70% | 23 min |
| NWS Bismarck, ND: flash flood warnings | 15 | 2 | 87% | 2 | 100% | 46 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 1, 3:59 PM CST | Winter Storm Watch | BIS | 13 hr |
| Jan 2, 5:09 AM CST | Winter Weather Advisory | BIS | 40 hr |
| Jan 3, 3:29 PM CST | Wind Chill Advisory | BIS | 25 hr |
| Jan 7, 5:20 AM CST | Winter Storm Watch | BIS | 23 hr |
| Jan 7, 3:42 PM CST | Winter Storm Warning | BIS | 48 hr |
| Jan 10, 3:05 PM CST | Blizzard Watch | BIS | 13 hr |
| Jan 11, 4:25 AM CST | Blizzard Warning | BIS | 32 hr |
| Jan 13, 4:51 AM CST | Wind Chill Advisory | BIS | 34 hr |
| Jan 13, 4:51 AM CST | Winter Weather Advisory | BIS | 19 hr |
| Jan 16, 8:52 PM CST | Winter Weather Advisory | BIS | 31 hr |
| Jan 22, 4:03 PM CST | Wind Chill Advisory | BIS | 4 days |
| Jan 22, 4:03 PM CST | Winter Weather Advisory | BIS | 14 hr |
| Jan 31, 4:43 AM CST | High Wind Warning | BIS | 13 hr |
| Feb 1, 4:14 AM CST | Wind Advisory | BIS | 15 hr |
| Feb 8, 4:15 PM CST | Winter Storm Warning | BIS | 59 hr |
| Feb 8, 4:15 PM CST | Winter Weather Advisory | BIS | 25 hr |
| Feb 9, 10:57 AM CST | Dense Fog Advisory | BIS | 10 hr |
| Feb 20, 4:00 AM CST | Winter Weather Advisory | BIS | 17 hr |
| Feb 23, 3:58 PM CST | Winter Weather Advisory | BIS | 23 hr |
| Feb 25, 3:21 PM CST | Wind Chill Advisory | BIS | 21 hr |
| Feb 26, 4:00 PM CST | Wind Chill Advisory | BIS | 20 hr |
| Mar 9, 4:26 AM CDT | Wind Chill Watch | BIS | 12 hr |
| Mar 9, 4:25 PM CDT | Wind Chill Advisory | BIS | 24 hr |
| Mar 10, 4:18 PM CDT | Wind Chill Warning | BIS | 20 hr |
| Mar 11, 11:55 AM CDT | Wind Chill Advisory | BIS | 24 hr |
| Mar 20, 3:09 PM CDT | Flood Watch | BIS | 4 days |
| Mar 21, 5:15 AM CDT | Blizzard Watch | BIS | 48 hr |
| Mar 22, 2:57 AM CDT | Areal Flood Advisory | BIS | 18 days |
| Mar 22, 10:22 AM CDT | Areal Flood Warning | BIS | 5 days |
| Mar 22, 5:04 PM CDT | Winter Weather Advisory | BIS | 42 hr |
| Mar 22, 10:03 PM CDT | Dense Fog Advisory | BIS | 156 days |
| Apr 9, 9:55 AM CDT | River Flood Warning | BIS | 47 hr |
| Apr 11, 9:18 AM CDT | River Flood Warning | BIS | 13 hr |
| Apr 12, 1:21 PM CDT | Areal Flood Warning | BIS | 8 days |
| May 5, 10:02 PM CDT | Severe Thunderstorm Warning | BIS | 58 min |
| May 13, 3:27 AM CDT | Wind Advisory | BIS | 18 hr |
| May 14, 3:15 PM CDT | Freeze Watch | BIS | 25 hr |
| May 15, 3:46 PM CDT | Freeze Warning | BIS | 17 hr |
| May 17, 4:57 AM CDT | Freeze Watch | BIS | 35 hr |
| May 20, 4:05 PM CDT | Frost Advisory | BIS | 17 hr |
| May 22, 3:45 PM CDT | Frost Advisory | BIS | 17 hr |
| May 24, 8:36 PM CDT | River Flood Warning | BIS | 39 hr |
| Jun 2, 3:32 PM CDT | Frost Advisory | BIS | 16 hr |
| Jun 7, 4:04 PM CDT | Frost Advisory | BIS | 15 hr |
| Jun 9, 3:36 PM CDT | Frost Advisory | BIS | 17 hr |
| Jun 21, 1:57 PM CDT | Mesoscale Discussion | SPC | 93 min |
| Jun 21, 7:40 PM CDT | Severe Thunderstorm Warning | BIS | 50 min |
| Jun 22, 1:29 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 22, 3:06 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 24, 1:46 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Jun 25, 9:05 PM CDT | Severe Thunderstorm Warning | BIS | 55 min |
| Jun 26, 1:09 AM CDT | Severe Thunderstorm Warning | BIS | 66 min |
| Jun 30, 4:19 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 30, 4:47 PM CDT | Severe Thunderstorm Warning | BIS | 58 min |
| Jun 30, 6:28 PM CDT | Severe Thunderstorm Warning | BIS | 48 min |
| Jun 30, 7:22 PM CDT | Mesoscale Discussion | SPC | 113 min |
| Jul 3, 8:59 PM CDT | Severe Thunderstorm Warning | BIS | 61 min |
| Jul 3, 9:45 PM CDT | Tornado Warning | BIS | 30 min |
| Jul 3, 9:54 PM CDT | Severe Thunderstorm Warning | BIS | 66 min |
| Jul 6, 11:30 PM CDT | Mesoscale Discussion | SPC | 60 min |
| Jul 8, 11:38 AM CDT | Mesoscale Discussion | SPC | 97 min |
| Jul 8, 2:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Jul 8, 3:20 PM CDT | Tornado Watch | SPC | 8 hr |
| Jul 8, 6:46 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Jul 8, 7:56 PM CDT | Severe Thunderstorm Warning | BIS | 64 min |
| Jul 8, 8:26 PM CDT | Severe Thunderstorm Warning | BIS | 64 min |
| Jul 8, 8:58 PM CDT | Severe Thunderstorm Warning | BIS | 62 min |
| Jul 8, 9:42 PM CDT | Mesoscale Discussion | SPC | 93 min |
| Jul 11, 8:01 PM CDT | Mesoscale Discussion | SPC | 59 min |
| Jul 11, 8:50 PM CDT | Tornado Warning | BIS | 25 min |
| Jul 13, 7:11 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 14, 12:33 AM CDT | Mesoscale Discussion | SPC | 87 min |
| Aug 14, 11:47 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Aug 19, 12:16 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Aug 23, 8:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Aug 23, 8:55 PM CDT | Tornado Watch | SPC | 5 hr |
| Aug 23, 11:12 PM CDT | Mesoscale Discussion | SPC | 93 min |
| Aug 23, 11:23 PM CDT | Areal Flood Advisory | BIS | 6 hr |
| Aug 23, 11:30 PM CDT | Severe Thunderstorm Warning | BIS | 60 min |
| Aug 23, 11:57 PM CDT | Tornado Warning | BIS | 33 min |
| Aug 24, 12:06 AM CDT | Flash Flood Warning | BIS | 5 hr |
| Aug 24, 12:29 AM CDT | Severe Thunderstorm Warning | BIS | 61 min |
| Aug 24, 1:15 AM CDT | Severe Thunderstorm Warning | BIS | 60 min |
| Aug 24, 1:27 AM CDT | Mesoscale Discussion | SPC | 33 min |
| Sep 18, 3:54 AM CDT | Fire Weather Watch | BIS | 25 hr |
| Sep 19, 4:31 AM CDT | Red Flag Warning | BIS | 15 hr |
| Sep 21, 3:48 PM CDT | Frost Advisory | BIS | 17 hr |
| Sep 24, 3:26 PM CDT | Fire Weather Watch | BIS | 37 hr |
| Sep 26, 3:56 AM CDT | Red Flag Warning | BIS | 17 hr |
| Sep 26, 3:20 PM CDT | Wind Advisory | BIS | 30 hr |
| Sep 27, 3:13 PM CDT | Frost Advisory | BIS | 18 hr |
| Sep 28, 4:13 AM CDT | Fire Weather Watch | BIS | 24 hr |
| Sep 29, 4:02 AM CDT | Red Flag Warning | BIS | 16 hr |
| Sep 30, 3:52 PM CDT | Wind Advisory | BIS | 30 hr |
| Oct 5, 4:14 AM CDT | Freeze Watch | BIS | 12 hr |
| Oct 5, 4:14 PM CDT | Freeze Warning | BIS | 18 hr |
| Oct 7, 4:18 AM CDT | Freeze Watch | BIS | 11 hr |
| Oct 7, 3:19 PM CDT | Freeze Warning | BIS | 21 hr |
| Oct 8, 4:54 AM CDT | Freeze Warning | BIS | 29 hr |
| Oct 14, 4:55 AM CDT | Winter Weather Advisory | BIS | 31 hr |
| Nov 30, 4:01 PM CST | Wind Advisory | BIS | 26 hr |
| Dec 8, 2:15 PM CST | Wind Chill Advisory | BIS | 44 hr |
| Dec 12, 4:57 AM CST | Wind Chill Advisory | BIS | 31 hr |
| Dec 12, 8:52 PM CST | Wind Chill Warning | BIS | 15 hr |
| Dec 12, 8:52 PM CST | Wind Chill Advisory | BIS | 39 hr |
| Dec 14, 4:04 PM CST | Wind Chill Warning | BIS | 20 hr |
| Dec 15, 12:54 PM CST | Wind Chill Advisory | BIS | 3 hr |
| Dec 18, 8:23 PM CST | Freezing Fog Advisory | BIS | 15 hr |
| Dec 20, 3:43 AM CST | Freezing Fog Advisory | BIS | 11 hr |
| Dec 22, 3:44 AM CST | Winter Storm Watch | BIS | 24 hr |
| Dec 23, 3:15 AM CST | Blizzard Watch | BIS | 37 hr |
| Dec 23, 3:15 AM CST | Winter Weather Advisory | BIS | 4 days |
| Dec 28, 10:20 AM CST | Freezing Fog Advisory | BIS | 3 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 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.