Alert archive / Colorado / Arapahoe County
Weather alerts in Arapahoe County, Colorado, 2010
143 weather alerts in 2010, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Arapahoe County and its neighbors
Each county as a circle sized by its count in 2010. Tap one for its archive.
- Alerts
- 143
- Warnings
- 53
- Watches
- 24
- Advisories
- 26
- Busiest month
- June32 alerts
- Busiest day
- April 22, 201011 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
3 of 11 tornado warnings covering Arapahoe County in 2010 had a tornado report inside them; 3 of 3 tornado reports fell inside a warning, on average 12 minutes after it went out.
Arapahoe County, 2010
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 11 | 3 | 73% | 3 | 100% | 12 min |
| Severe thunderstorm warnings | 18 | 11 | 39% | 23 | 17% | 20 min |
| Flash flood warnings | 1 | 0 | 100% | 0 |
Each office's whole area, 2010
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Denver/Boulder, CO: tornado warnings | 80 | 21 | 74% | 36 | 69% | 14 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 153 | 68 | 56% | 268 | 54% | 23 min |
| NWS Denver/Boulder, CO: flash flood warnings | 22 | 3 | 86% | 6 | 100% | 50 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, Mountain Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 5, 3:33 PM MST | Winter Weather Advisory | BOU | 35 hr |
| Jan 7, 2:20 AM MST | Wind Chill Advisory | BOU | 9 hr |
| Feb 18, 1:56 PM MST | Winter Weather Advisory | BOU | 12 hr |
| Mar 14, 5:47 AM MDT | Winter Weather Advisory | BOU | 20 hr |
| Mar 17, 2:56 PM MDT | Winter Storm Watch | BOU | 22 hr |
| Mar 18, 6:19 AM MDT | Winter Storm Warning | BOU | 42 hr |
| Mar 18, 12:55 PM MDT | Winter Weather Advisory | BOU | 35 hr |
| Mar 22, 2:58 PM MDT | Winter Storm Warning | BOU | 44 hr |
| Mar 22, 2:58 PM MDT | Winter Weather Advisory | BOU | 44 hr |
| Mar 23, 6:21 PM MDT | Mesoscale Discussion | SPC | 6 hr |
| Mar 25, 4:23 AM MDT | Winter Storm Watch | BOU | 25 hr |
| Mar 26, 5:08 AM MDT | Winter Storm Warning | BOU | 15 hr |
| Mar 26, 5:08 AM MDT | Winter Weather Advisory | BOU | 14 hr |
| Apr 3, 6:37 AM MDT | Red Flag Warning | BOU | 13 hr |
| Apr 4, 3:01 AM MDT | Fire Weather Watch | BOU | 27 hr |
| Apr 5, 5:48 AM MDT | Red Flag Warning | BOU | 14 hr |
| Apr 11, 2:47 PM MDT | Red Flag Warning | BOU | 29 hr |
| Apr 21, 4:42 PM MDT | Severe Thunderstorm Warning | BOU | 48 min |
| Apr 21, 5:58 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Apr 22, 11:19 AM MDT | Winter Storm Watch | BOU | 18 hr |
| Apr 22, 11:19 AM MDT | Winter Storm Warning | BOU | 46 hr |
| Apr 22, 11:19 AM MDT | Winter Weather Advisory | BOU | 41 hr |
| Apr 22, 12:30 PM MDT | Tornado Watch | SPC | 8 hr |
| Apr 22, 1:34 PM MDT | Tornado Warning | BOU | 41 min |
| Apr 22, 2:10 PM MDT | Severe Thunderstorm Warning | BOU | 52 min |
| Apr 22, 2:21 PM MDT | Mesoscale Discussion | SPC | 54 min |
| Apr 22, 2:43 PM MDT | Tornado Warning | BOU | 10 min |
| Apr 22, 2:57 PM MDT | Tornado Warning | BOU | 48 min |
| Apr 22, 3:29 PM MDT | Tornado Warning | BOU | 16 min |
| Apr 22, 3:36 PM MDT | Tornado Warning | BOU | 28 min |
| Apr 24, 4:01 PM MDT | Frost Advisory | BOU | 16 hr |
| May 9, 3:04 PM MDT | Winter Storm Watch | BOU | 45 hr |
| May 11, 7:22 PM MDT | Special Weather Statement | BOU | 53 min |
| May 11, 8:19 PM MDT | Special Weather Statement | BOU | 41 min |
| May 11, 9:13 PM MDT | Special Weather Statement | BOU | 62 min |
| May 12, 2:59 PM MDT | Freeze Warning | BOU | 7 hr |
| May 15, 12:24 PM MDT | Special Weather Statement | BOU | 36 min |
| May 15, 12:37 PM MDT | Mesoscale Discussion | SPC | 83 min |
| May 18, 11:42 AM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 18, 12:41 PM MDT | Tornado Watch | SPC | 10 hr |
| May 18, 6:50 PM MDT | Mesoscale Discussion | SPC | 55 min |
| May 21, 1:30 PM MDT | Mesoscale Discussion | SPC | 60 min |
| May 24, 9:58 AM MDT | High Wind Warning | BOU | 7 hr |
| May 26, 1:26 PM MDT | Mesoscale Discussion | SPC | 64 min |
| May 26, 1:49 PM MDT | Tornado Watch | SPC | 7 hr |
| May 26, 5:33 PM MDT | Tornado Warning | BOU | 42 min |
| May 26, 6:14 PM MDT | Tornado Warning | BOU | 19 min |
| May 26, 6:30 PM MDT | Mesoscale Discussion | SPC | 90 min |
| May 29, 2:58 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 6, 1:48 PM MDT | Mesoscale Discussion | SPC | 117 min |
| Jun 6, 2:24 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 6, 8:03 PM MDT | Mesoscale Discussion | SPC | 87 min |
| Jun 7, 1:34 PM MDT | Mesoscale Discussion | SPC | 86 min |
| Jun 7, 4:17 PM MDT | Mesoscale Discussion | SPC | 88 min |
| Jun 8, 7:41 PM MDT | Special Weather Statement | BOU | 49 min |
| Jun 9, 1:55 PM MDT | Mesoscale Discussion | SPC | 65 min |
| Jun 9, 2:39 PM MDT | Tornado Watch | SPC | 6 hr |
| Jun 10, 4:44 PM MDT | Tornado Watch | SPC | 6 hr |
| Jun 10, 4:45 PM MDT | Severe Thunderstorm Warning | BOU | 60 min |
| Jun 10, 5:43 PM MDT | Severe Thunderstorm Warning | BOU | 62 min |
| Jun 10, 6:37 PM MDT | Tornado Warning | BOU | 38 min |
| Jun 10, 7:09 PM MDT | Tornado Warning | BOU | 51 min |
| Jun 10, 7:21 PM MDT | Areal Flood Advisory | BOU | 84 min |
| Jun 10, 8:05 PM MDT | Severe Thunderstorm Warning | BOU | 55 min |
| Jun 10, 8:17 PM MDT | Mesoscale Discussion | SPC | 58 min |
| Jun 10, 8:54 PM MDT | Severe Thunderstorm Warning | BOU | 66 min |
| Jun 11, 1:09 PM MDT | Mesoscale Discussion | SPC | 96 min |
| Jun 11, 2:13 PM MDT | Tornado Watch | SPC | 7 hr |
| Jun 11, 5:35 PM MDT | Mesoscale Discussion | SPC | 55 min |
| Jun 11, 5:37 PM MDT | Severe Thunderstorm Warning | BOU | 53 min |
| Jun 11, 5:49 PM MDT | Areal Flood Advisory | BOU | 86 min |
| Jun 11, 6:08 PM MDT | Tornado Warning | BOU | 52 min |
| Jun 11, 6:59 PM MDT | Severe Thunderstorm Warning | BOU | 38 min |
| Jun 11, 8:13 PM MDT | Mesoscale Discussion | SPC | 62 min |
| Jun 18, 8:45 PM MDT | Severe Thunderstorm Warning | BOU | 45 min |
| Jun 19, 4:12 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 20, 1:30 PM MDT | Tornado Watch | SPC | 7 hr |
| Jun 20, 4:23 PM MDT | Mesoscale Discussion | SPC | 67 min |
| Jun 21, 2:31 PM MDT | Mesoscale Discussion | SPC | 89 min |
| Jun 27, 7:44 PM MDT | Special Weather Statement | BOU | 31 min |
| Jun 27, 8:40 PM MDT | Areal Flood Advisory | BOU | 80 min |
| Jul 2, 12:19 PM MDT | Mesoscale Discussion | SPC | 56 min |
| Jul 2, 1:00 PM MDT | Special Weather Statement | BOU | 30 min |
| Jul 2, 1:51 PM MDT | Severe Thunderstorm Warning | BOU | 39 min |
| Jul 4, 12:39 PM MDT | Tornado Watch | SPC | 8 hr |
| Jul 4, 3:57 PM MDT | Severe Thunderstorm Warning | BOU | 48 min |
| Jul 4, 4:38 PM MDT | Areal Flood Advisory | BOU | 82 min |
| Jul 4, 5:22 PM MDT | Severe Thunderstorm Warning | BOU | 38 min |
| Jul 4, 6:08 PM MDT | Mesoscale Discussion | SPC | 97 min |
| Jul 4, 6:31 PM MDT | Severe Thunderstorm Warning | BOU | 29 min |
| Jul 6, 4:33 PM MDT | Severe Thunderstorm Warning | BOU | 42 min |
| Jul 6, 6:41 PM MDT | Severe Thunderstorm Warning | BOU | 49 min |
| Jul 6, 7:21 PM MDT | Mesoscale Discussion | SPC | 54 min |
| Jul 6, 7:27 PM MDT | Flash Flood Warning | BOU | 2 hr |
| Jul 8, 1:31 PM MDT | Mesoscale Discussion | SPC | 59 min |
| Jul 9, 2:22 PM MDT | Mesoscale Discussion | SPC | 113 min |
| Jul 9, 8:53 PM MDT | Special Weather Statement | BOU | 37 min |
| Jul 15, 6:12 PM MDT | Mesoscale Discussion | SPC | 93 min |
| Jul 18, 4:50 PM MDT | Special Weather Statement | BOU | 40 min |
| Jul 21, 3:32 PM MDT | Severe Thunderstorm Warning | BOU | 43 min |
| Jul 21, 3:42 PM MDT | Mesoscale Discussion | SPC | 63 min |
| Jul 21, 4:04 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 21, 4:20 PM MDT | Areal Flood Advisory | BOU | 85 min |
| Jul 27, 5:33 PM MDT | Special Weather Statement | BOU | 42 min |
| Jul 30, 4:24 AM MDT | Flash Flood Watch | BOU | 17 hr |
| Jul 30, 5:29 PM MDT | Areal Flood Advisory | BOU | 79 min |
| Jul 30, 6:33 PM MDT | Areal Flood Advisory | BOU | 79 min |
| Jul 31, 4:26 AM MDT | Flash Flood Watch | BOU | 17 hr |
| Aug 4, 4:35 PM MDT | Areal Flood Advisory | BOU | 115 min |
| Aug 4, 5:32 PM MDT | Special Weather Statement | BOU | 43 min |
| Aug 16, 1:08 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 16, 1:55 PM MDT | Tornado Warning | BOU | 41 min |
| Aug 16, 2:34 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 16, 5:44 PM MDT | Mesoscale Discussion | SPC | 61 min |
| Aug 19, 8:14 PM MDT | Severe Thunderstorm Warning | BOU | 23 min |
| Sep 4, 3:46 AM MDT | Fire Weather Watch | BOU | 11 hr |
| Sep 4, 3:08 PM MDT | Red Flag Warning | BOU | 30 hr |
| Sep 7, 4:08 AM MDT | Red Flag Warning | BOU | 16 hr |
| Sep 8, 2:57 PM MDT | Fire Weather Watch | BOU | 24 hr |
| Sep 8, 2:57 PM MDT | Red Flag Warning | BOU | 51 hr |
| Sep 19, 4:24 AM MDT | Fire Weather Watch | BOU | 10 hr |
| Sep 19, 2:03 PM MDT | Red Flag Warning | BOU | 31 hr |
| Sep 27, 1:37 AM MDT | Red Flag Warning | BOU | 14 hr |
| Sep 29, 3:50 AM MDT | Red Flag Warning | BOU | 11 hr |
| Oct 12, 4:07 AM MDT | Frost Advisory | BOU | 29 hr |
| Oct 18, 3:56 PM MDT | Frost Advisory | BOU | 17 hr |
| Oct 25, 4:26 AM MDT | Freeze Warning | BOU | 27 hr |
| Oct 26, 1:29 PM MDT | Red Flag Warning | BOU | 5 hr |
| Oct 26, 3:07 PM MDT | Fire Weather Watch | BOU | 13 hr |
| Oct 26, 7:20 PM MDT | Freeze Warning | BOU | 14 hr |
| Oct 27, 4:09 AM MDT | Red Flag Warning | BOU | 15 hr |
| Oct 27, 3:14 PM MDT | Freeze Warning | BOU | 18 hr |
| Oct 29, 9:12 AM MDT | Red Flag Warning | BOU | 9 hr |
| Nov 17, 12:36 AM MST | Blizzard Warning | BOU | 4 hr |
| Nov 20, 10:49 PM MST | Dense Fog Advisory | BOU | 11 hr |
| Nov 21, 6:32 PM MST | Dense Fog Advisory | BOU | 10 hr |
| Nov 28, 10:09 AM MST | Winter Weather Advisory | BOU | 21 hr |
| Dec 14, 3:16 PM MST | Winter Weather Advisory | BOU | 32 hr |
| Dec 29, 3:29 AM MST | Winter Storm Watch | BOU | 13 hr |
| Dec 29, 3:27 PM MST | Winter Storm Warning | BOU | 44 hr |
| Dec 29, 3:27 PM MST | Winter Weather Advisory | BOU | 47 hr |
| Dec 31, 6:09 AM MST | Wind Chill Advisory | BOU | 6 hr |
| Dec 31, 2:45 PM MST | Wind Chill Advisory | BOU | 19 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 | 18 |
| Tornado Warning | 11 |
| Severe Thunderstorm Watch | 4 |
| Tornado Watch | 8 |
| Mesoscale Discussion | 29 |
| Special Weather Statement | 11 |
| Flooding | |
| Flash Flood Warning | 1 |
| Flash Flood Watch | 2 |
| Areal Flood Advisory | 8 |
| Winter | |
| Blizzard Warning | 1 |
| Winter Storm Warning | 5 |
| Winter Storm Watch | 5 |
| Winter Weather Advisory | 10 |
| Cold | |
| Freeze Warning | 4 |
| Frost Advisory | 3 |
| Wind Chill Advisory | 3 |
| Wind and dust | |
| High Wind Warning | 1 |
| Fire | |
| Red Flag Warning | 12 |
| Fire Weather Watch | 5 |
| Fog and smoke | |
| Dense Fog Advisory | 2 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20092011
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.