Alert archive / Colorado / Grand County
Weather alerts in Grand County, Colorado, 2024
99 weather alerts in 2024, 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 2024. Tap one for its archive.
- Alerts
- 99
- Warnings
- 29
- Watches
- 21
- Advisories
- 40
- Busiest month
- June14 alerts
- Busiest day
- January 16, 20244 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, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 0 | 1 | 0% | |||
| Flash flood warnings | 1 | 0 | 100% | 0 |
Each office's whole area, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Denver/Boulder, CO: tornado warnings | 27 | 2 | 93% | 15 | 20% | 11 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 295 | 119 | 60% | 339 | 79% | 20 min |
| NWS Denver/Boulder, CO: flash flood warnings | 32 | 9 | 72% | 14 | 79% | 40 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, 1:41 PM MST | Winter Weather Advisory | BOU | 45 hr |
| Jan 10, 1:41 PM MST | Winter Weather Advisory | BOU | 22 hr |
| Jan 11, 3:10 AM MST | Winter Storm Watch | BOU | 9 hr |
| Jan 11, 11:59 AM MST | Winter Storm Warning | BOU | 4 days |
| Jan 12, 5:25 PM MST | Winter Weather Advisory | BOU | 72 hr |
| Jan 16, 3:53 AM MST | Winter Storm Watch | BOU | 11 hr |
| Jan 16, 3:53 AM MST | Winter Storm Warning | BOU | 61 hr |
| Jan 16, 3:53 AM MST | Winter Weather Advisory | BOU | 55 hr |
| Jan 16, 2:05 PM MST | High Wind Warning | BOU | 17 hr |
| Feb 1, 2:13 AM MST | Winter Storm Watch | BOU | 12 hr |
| Feb 1, 2:09 PM MST | Winter Storm Warning | BOU | 54 hr |
| Feb 1, 2:09 PM MST | Winter Weather Advisory | BOU | 54 hr |
| Feb 6, 1:43 AM MST | Winter Storm Watch | BOU | 13 hr |
| Feb 6, 2:24 PM MST | Winter Storm Warning | BOU | 48 hr |
| Feb 7, 3:32 AM MST | Winter Weather Advisory | BOU | 35 hr |
| Feb 7, 3:33 AM MST | High Wind Watch | BOU | 10 hr |
| Feb 14, 2:18 PM MST | Winter Weather Advisory | BOU | 63 hr |
| Feb 20, 2:43 AM MST | Winter Weather Advisory | BOU | 50 hr |
| Feb 24, 12:31 PM MST | Winter Storm Watch | BOU | 24 hr |
| Feb 25, 12:59 PM MST | Winter Storm Warning | BOU | 58 hr |
| Mar 1, 5:42 AM MST | Winter Storm Watch | BOU | 9 hr |
| Mar 1, 2:21 PM MST | Winter Storm Warning | BOU | 67 hr |
| Mar 2, 9:48 AM MST | Winter Weather Advisory | BOU | 47 hr |
| Mar 4, 8:48 AM MST | Winter Weather Advisory | BOU | 15 hr |
| Mar 6, 1:50 AM MST | Winter Storm Watch | BOU | 24 hr |
| Mar 7, 1:50 AM MST | Winter Weather Advisory | BOU | 39 hr |
| Mar 11, 2:29 PM MDT | Winter Storm Watch | BOU | 47 hr |
| Mar 12, 4:17 AM MDT | Winter Weather Advisory | BOU | 3 days |
| Mar 12, 2:12 PM MDT | Winter Storm Warning | BOU | 64 hr |
| Mar 23, 3:22 AM MDT | Winter Weather Advisory | BOU | 57 hr |
| Mar 24, 3:53 AM MDT | Winter Storm Warning | BOU | 26 hr |
| Mar 28, 2:25 PM MDT | Winter Weather Advisory | BOU | 40 hr |
| Apr 4, 2:58 PM MDT | High Wind Watch | BOU | 36 hr |
| Apr 5, 2:52 AM MDT | Winter Weather Advisory | BOU | 57 hr |
| Apr 5, 11:50 AM MDT | High Wind Warning | BOU | 54 hr |
| Apr 14, 2:26 PM MDT | Winter Storm Watch | BOU | 12 hr |
| Apr 15, 2:42 AM MDT | Winter Storm Warning | BOU | 36 hr |
| Apr 15, 2:42 AM MDT | Winter Weather Advisory | BOU | 36 hr |
| Apr 19, 3:22 AM MDT | Winter Weather Advisory | BOU | 30 hr |
| Apr 25, 1:51 PM MDT | Winter Storm Watch | BOU | 24 hr |
| Apr 26, 1:36 PM MDT | Winter Storm Warning | BOU | 34 hr |
| May 5, 3:13 AM MDT | Winter Weather Advisory | BOU | 39 hr |
| May 5, 3:14 AM MDT | High Wind Watch | BOU | 11 hr |
| May 7, 3:09 AM MDT | Winter Weather Advisory | BOU | 21 hr |
| May 9, 3:35 AM MDT | Winter Weather Advisory | BOU | 30 hr |
| May 12, 12:31 AM MDT | Winter Weather Advisory | BOU | 14 hr |
| Jun 5, 3:32 PM MDT | River Flood Advisory | BOU | 11 days |
| Jun 5, 3:32 PM MDT | River Flood Advisory | BOU | 11 days |
| Jun 8, 5:48 PM MDT | Areal Flood Advisory | BOU | 112 min |
| Jun 15, 2:32 PM MDT | Red Flag Warning | BOU | 27 hr |
| Jun 16, 2:42 PM MDT | Red Flag Warning | BOU | 30 hr |
| Jun 20, 12:09 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 21, 7:28 PM MDT | Special Weather Statement | BOU | 47 min |
| Jun 24, 1:55 PM MDT | Special Weather Statement | BOU | 50 min |
| Jun 27, 5:06 PM MDT | Special Weather Statement | BOU | 24 min |
| Jun 27, 5:58 PM MDT | Special Weather Statement | BOU | 32 min |
| Jun 28, 3:43 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Jun 28, 4:08 PM MDT | Mesoscale Discussion | SPC | 97 min |
| Jun 28, 4:17 PM MDT | Flash Flood Warning | BOU | 119 min |
| Jun 28, 4:28 PM MDT | Special Weather Statement | BOU | 47 min |
| Jul 13, 7:59 PM MDT | Fire Weather Watch | BOU | 8 hr |
| Jul 14, 4:25 AM MDT | Red Flag Warning | BOU | 17 hr |
| Jul 21, 12:55 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Jul 30, 3:02 AM MDT | Red Flag Warning | BOU | 17 hr |
| Aug 13, 10:29 AM MDT | Flood Watch | BOU | 10 hr |
| Sep 4, 12:06 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Sep 5, 7:15 AM MDT | Dense Fog Advisory | BOU | 105 min |
| Sep 10, 2:01 PM MDT | Fire Weather Watch | BOU | 24 hr |
| Sep 11, 2:14 PM MDT | Red Flag Warning | BOU | 30 hr |
| Sep 17, 10:33 AM MDT | Mesoscale Discussion | SPC | 117 min |
| Sep 20, 2:51 PM MDT | Winter Weather Advisory | BOU | 42 hr |
| Sep 29, 1:13 PM MDT | Fire Weather Watch | BOU | 39 hr |
| Oct 1, 3:56 AM MDT | Fire Weather Watch | BOU | 11 hr |
| Oct 1, 3:56 AM MDT | Red Flag Warning | BOU | 15 hr |
| Oct 1, 2:33 PM MDT | Red Flag Warning | BOU | 28 hr |
| Oct 3, 2:18 PM MDT | Fire Weather Watch | BOU | 23 hr |
| Oct 3, 2:18 PM MDT | Red Flag Warning | BOU | 29 hr |
| Oct 4, 1:27 PM MDT | Red Flag Warning | BOU | 30 hr |
| Oct 21, 2:05 AM MDT | Winter Weather Advisory | BOU | 10 hr |
| Nov 2, 2:34 PM MDT | Winter Weather Advisory | BOU | 43 hr |
| Nov 3, 2:06 PM MST | Winter Storm Warning | BOU | 19 hr |
| Nov 5, 3:38 AM MST | Winter Weather Advisory | BOU | 61 hr |
| Nov 7, 3:51 AM MST | Winter Storm Watch | BOU | 10 hr |
| Nov 7, 1:43 PM MST | Winter Weather Advisory | BOU | 46 hr |
| Nov 12, 3:41 AM MST | Winter Weather Advisory | BOU | 25 hr |
| Nov 23, 3:41 AM MST | Winter Weather Advisory | BOU | 45 hr |
| Nov 24, 1:38 PM MST | Winter Storm Watch | BOU | 12 hr |
| Nov 25, 1:15 AM MST | Winter Storm Warning | BOU | 61 hr |
| Nov 25, 1:15 AM MST | Winter Weather Advisory | BOU | 61 hr |
| Dec 15, 2:52 AM MST | High Wind Warning | BOU | 23 hr |
| Dec 17, 2:54 AM MST | Winter Weather Advisory | BOU | 17 hr |
| Dec 18, 9:53 AM MST | High Wind Warning | BOU | 20 hr |
| Dec 26, 2:05 PM MST | Winter Storm Warning | BOU | 40 hr |
| Dec 26, 2:05 PM MST | Winter Weather Advisory | BOU | 15 hr |
| Dec 26, 2:05 PM MST | Winter Weather Advisory | BOU | 40 hr |
| Dec 27, 2:29 PM MST | Winter Storm Warning | BOU | 45 hr |
| Dec 27, 2:29 PM MST | Winter Weather Advisory | BOU | 45 hr |
| Dec 28, 1:52 PM MST | Winter Storm Warning | BOU | 51 hr |
| Dec 28, 1:52 PM MST | Winter Weather Advisory | BOU | 51 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 | |
| Mesoscale Discussion | 4 |
| Special Weather Statement | 5 |
| Flooding | |
| Flash Flood Warning | 1 |
| Flood Watch | 1 |
| Areal Flood Advisory | 3 |
| River Flood Advisory | 2 |
| Winter | |
| Winter Storm Warning | 15 |
| Winter Storm Watch | 12 |
| Winter Weather Advisory | 34 |
| Wind and dust | |
| High Wind Warning | 4 |
| High Wind Watch | 3 |
| Fire | |
| Red Flag Warning | 9 |
| Fire Weather Watch | 5 |
| Fog and smoke | |
| Dense Fog Advisory | 1 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20232025
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.