Alert archive / Colorado / Grand County
Weather alerts in Grand County, Colorado, 2011
108 weather alerts in 2011, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Grand County and its neighbors
Each county as a circle sized by its count in 2011. Tap one for its archive.
- Alerts
- 108
- Warnings
- 25
- Watches
- 18
- Advisories
- 56
- Busiest month
- June22 alerts
- Busiest day
- June 30, 201110 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Grand County, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 7 | 1 | 86% | 1 | 100% | 36 min |
| Flash flood warnings | 1 | 0 | 100% | 0 |
Each office's whole area, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Denver/Boulder, CO: tornado warnings | 35 | 6 | 83% | 11 | 73% | 12 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 212 | 85 | 60% | 251 | 65% | 19 min |
| NWS Denver/Boulder, CO: flash flood warnings | 36 | 6 | 83% | 7 | 86% | 68 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 8, 3:52 PM MST | Winter Weather Advisory | BOU | 41 hr |
| Jan 15, 3:18 PM MST | Winter Storm Watch | BOU | 13 hr |
| Jan 16, 3:50 AM MST | Winter Storm Warning | BOU | 54 hr |
| Jan 16, 4:09 PM MST | Winter Weather Advisory | BOU | 24 hr |
| Jan 19, 4:23 AM MST | Winter Weather Advisory | BOU | 18 hr |
| Jan 21, 4:39 AM MST | Winter Weather Advisory | BOU | 41 hr |
| Jan 31, 4:10 PM MST | Wind Chill Warning | BOU | 44 hr |
| Feb 4, 3:29 PM MST | Winter Storm Warning | BOU | 39 hr |
| Feb 4, 3:29 PM MST | Winter Weather Advisory | BOU | 18 hr |
| Feb 6, 3:52 PM MST | Winter Weather Advisory | BOU | 44 hr |
| Feb 7, 3:44 PM MST | Winter Storm Warning | BOU | 12 hr |
| Feb 15, 3:14 PM MST | Winter Storm Watch | BOU | 12 hr |
| Feb 16, 3:03 AM MST | Winter Storm Warning | BOU | 37 hr |
| Feb 16, 3:03 AM MST | Winter Weather Advisory | BOU | 37 hr |
| Feb 19, 3:47 AM MST | Winter Weather Advisory | BOU | 38 hr |
| Feb 23, 2:05 PM MST | Winter Storm Watch | BOU | 22 hr |
| Feb 24, 12:15 PM MST | Winter Weather Advisory | BOU | 39 hr |
| Mar 6, 2:52 PM MST | Winter Weather Advisory | BOU | 37 hr |
| Mar 10, 3:19 AM MST | High Wind Watch | BOU | 12 hr |
| Mar 15, 2:48 PM MDT | Winter Storm Watch | BOU | 24 hr |
| Mar 16, 3:11 PM MDT | Winter Storm Warning | BOU | 37 hr |
| Mar 17, 3:55 PM MDT | Winter Weather Advisory | BOU | 12 hr |
| Mar 28, 12:29 PM MDT | Winter Weather Advisory | BOU | 12 hr |
| Apr 2, 3:33 AM MDT | Winter Storm Watch | BOU | 13 hr |
| Apr 2, 4:51 PM MDT | Winter Storm Warning | BOU | 28 hr |
| Apr 2, 4:51 PM MDT | Winter Weather Advisory | BOU | 28 hr |
| Apr 10, 4:28 AM MDT | Winter Weather Advisory | BOU | 17 hr |
| Apr 13, 4:06 AM MDT | Winter Weather Advisory | BOU | 29 hr |
| Apr 17, 3:42 PM MDT | Winter Storm Watch | BOU | 12 hr |
| Apr 18, 3:33 AM MDT | Winter Storm Warning | BOU | 25 hr |
| Apr 18, 3:33 AM MDT | Winter Weather Advisory | BOU | 25 hr |
| Apr 21, 4:52 PM MDT | Mesoscale Discussion | SPC | 53 min |
| Apr 23, 4:05 AM MDT | Winter Weather Advisory | BOU | 24 hr |
| Apr 24, 3:53 AM MDT | Winter Weather Advisory | BOU | 24 hr |
| Apr 25, 3:33 PM MDT | Winter Weather Advisory | BOU | 19 hr |
| Apr 26, 10:55 AM MDT | Winter Storm Warning | BOU | 13 hr |
| Apr 29, 10:50 AM MDT | Winter Weather Advisory | BOU | 18 hr |
| May 10, 3:09 PM MDT | Winter Weather Advisory | BOU | 20 hr |
| May 11, 10:46 AM MDT | Winter Storm Warning | BOU | 19 hr |
| May 18, 4:43 AM MDT | Winter Storm Warning | BOU | 24 hr |
| May 18, 4:43 AM MDT | Winter Weather Advisory | BOU | 24 hr |
| May 20, 4:28 AM MDT | Winter Weather Advisory | BOU | 12 hr |
| May 29, 9:42 PM MDT | Areal Flood Advisory | BOU | 4 days |
| Jun 2, 2:46 PM MDT | Areal Flood Advisory | BOU | 71 hr |
| Jun 5, 11:46 AM MDT | Areal Flood Advisory | BOU | 72 hr |
| Jun 8, 12:41 PM MDT | Areal Flood Advisory | BOU | 72 hr |
| Jun 11, 12:44 PM MDT | Areal Flood Advisory | BOU | 71 hr |
| Jun 15, 6:50 PM MDT | Red Flag Warning | BOU | 25 hr |
| Jun 16, 2:45 PM MDT | Areal Flood Advisory | BOU | 9 days |
| Jun 19, 11:42 AM MDT | Winter Weather Advisory | BOU | 23 hr |
| Jun 24, 3:04 PM MDT | River Flood Advisory | BOU | 5 days |
| Jun 25, 11:42 AM MDT | River Flood Advisory | BOU | 5 days |
| Jun 25, 11:42 AM MDT | River Flood Advisory | BOU | 9 days |
| Jun 29, 5:06 PM MDT | Severe Thunderstorm Warning | BOU | 54 min |
| Jun 29, 5:09 PM MDT | Areal Flood Advisory | BOU | 25 hr |
| Jun 30, 11:57 AM MDT | Mesoscale Discussion | SPC | 63 min |
| Jun 30, 12:18 PM MDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jun 30, 1:49 PM MDT | Mesoscale Discussion | SPC | 116 min |
| Jun 30, 1:50 PM MDT | Severe Thunderstorm Warning | BOU | 19 min |
| Jun 30, 3:59 PM MDT | Severe Thunderstorm Warning | BOU | 61 min |
| Jun 30, 4:17 PM MDT | Mesoscale Discussion | SPC | 118 min |
| Jun 30, 4:50 PM MDT | Severe Thunderstorm Warning | BOU | 36 min |
| Jun 30, 5:14 PM MDT | Severe Thunderstorm Warning | BOU | 61 min |
| Jun 30, 5:14 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jun 30, 5:43 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Jun 30, 6:28 PM MDT | Areal Flood Advisory | BOU | 5 days |
| Jun 30, 7:25 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 4, 12:18 PM MDT | Hydrologic Advisory | BOU | 53 hr |
| Jul 5, 5:34 PM MDT | Flash Flood Warning | BOU | 86 min |
| Jul 5, 11:07 PM MDT | Areal Flood Advisory | BOU | 36 hr |
| Jul 6, 10:07 PM MDT | Areal Flood Advisory | BOU | 7 days |
| Jul 12, 3:49 AM MDT | Flash Flood Watch | BOU | 25 hr |
| Jul 12, 2:02 PM MDT | River Flood Advisory | BOU | 54 hr |
| Jul 13, 6:54 PM MDT | Areal Flood Advisory | BOU | 22 hr |
| Jul 14, 4:31 PM MDT | Areal Flood Advisory | BOU | 71 hr |
| Jul 17, 12:55 PM MDT | Areal Flood Advisory | BOU | 80 min |
| Jul 17, 6:20 PM MDT | Special Weather Statement | BOU | 25 min |
| Jul 18, 9:28 PM MDT | Areal Flood Advisory | BOU | 24 hr |
| Jul 19, 11:13 AM MDT | Flash Flood Watch | BOU | 9 hr |
| Jul 20, 9:51 AM MDT | River Flood Advisory | BOU | 51 hr |
| Aug 2, 4:17 AM MDT | Flash Flood Watch | BOU | 16 hr |
| Aug 3, 1:39 PM MDT | Areal Flood Advisory | BOU | 64 min |
| Aug 16, 1:48 PM MDT | Mesoscale Discussion | SPC | 117 min |
| Sep 14, 2:53 PM MDT | Winter Weather Advisory | BOU | 13 hr |
| Oct 5, 3:35 PM MDT | Winter Weather Advisory | BOU | 28 hr |
| Oct 7, 5:00 AM MDT | Winter Storm Watch | BOU | 7 hr |
| Oct 7, 12:20 PM MDT | Winter Weather Advisory | BOU | 30 hr |
| Oct 16, 12:03 PM MDT | Winter Weather Advisory | BOU | 26 hr |
| Oct 23, 3:29 PM MDT | Winter Storm Watch | BOU | 36 hr |
| Oct 25, 3:49 AM MDT | Winter Storm Warning | BOU | 37 hr |
| Oct 25, 5:56 PM MDT | Mesoscale Discussion | SPC | 4 hr |
| Oct 31, 5:02 AM MDT | Winter Storm Watch | BOU | 24 hr |
| Nov 1, 5:12 AM MDT | Winter Weather Advisory | BOU | 29 hr |
| Nov 1, 10:54 AM MDT | Winter Storm Warning | BOU | 25 hr |
| Nov 1, 7:13 PM MDT | Mesoscale Discussion | SPC | 5 hr |
| Nov 4, 3:07 PM MDT | Winter Weather Advisory | BOU | 33 hr |
| Nov 10, 3:39 PM MST | Winter Storm Watch | BOU | 19 hr |
| Nov 11, 10:23 AM MST | Winter Storm Warning | BOU | 62 hr |
| Nov 11, 10:23 AM MST | Winter Weather Advisory | BOU | 54 hr |
| Nov 18, 3:47 PM MST | Winter Weather Advisory | BOU | 19 hr |
| Nov 19, 2:07 PM MST | Winter Weather Advisory | BOU | 9 hr |
| Nov 29, 12:14 PM MST | Winter Storm Watch | BOU | 23 hr |
| Nov 30, 11:27 AM MST | Winter Weather Advisory | BOU | 27 hr |
| Dec 21, 4:33 AM MST | Winter Weather Advisory | BOU | 30 hr |
| Dec 28, 5:24 AM MST | High Wind Watch | BOU | 5 hr |
| Dec 28, 10:32 AM MST | High Wind Warning | BOU | 30 hr |
| Dec 29, 3:03 PM MST | High Wind Watch | BOU | 19 hr |
| Dec 30, 10:15 AM MST | High Wind Warning | BOU | 31 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 | 7 |
| Severe Thunderstorm Watch | 1 |
| Mesoscale Discussion | 8 |
| Special Weather Statement | 1 |
| Flooding | |
| Flash Flood Warning | 1 |
| Flash Flood Watch | 3 |
| Areal Flood Advisory | 15 |
| Hydrologic Advisory | 1 |
| River Flood Advisory | 5 |
| Winter | |
| Winter Storm Warning | 13 |
| Winter Storm Watch | 11 |
| Winter Weather Advisory | 35 |
| Cold | |
| Wind Chill Warning | 1 |
| Wind and dust | |
| High Wind Warning | 2 |
| High Wind Watch | 3 |
| Fire | |
| Red Flag Warning | 1 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20102012
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.