Alert archive / Utah / San Juan County
Weather alerts in San Juan County, Utah, 2017
88 weather alerts in 2017, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
San Juan County and its neighbors
Each county as a circle sized by its count in 2017. Tap one for its archive.
- Alerts
- 88
- Warnings
- 28
- Watches
- 17
- Advisories
- 33
- Busiest month
- July25 alerts
- Busiest day
- July 25, 20177 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
San Juan County, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 6 | 0 | 100% | 0 | ||
| Flash flood warnings | 5 | 0 | 100% | 2 | 0% |
Each office's whole area, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Salt Lake City, UT: severe thunderstorm warnings | 29 | 12 | 59% | 69 | 30% | 32 min |
| NWS Salt Lake City, UT: flash flood warnings | 49 | 10 | 80% | 25 | 48% | 103 min |
| NWS Grand Junction, CO: severe thunderstorm warnings | 14 | 2 | 86% | 25 | 8% | 7 min |
| NWS Grand Junction, CO: flash flood warnings | 13 | 1 | 92% | 24 | 4% | 52 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 |
|---|---|---|---|
| Dec 31, 6:44 PM MST | Dense Fog Advisory | GJT | 14 hr |
| Jan 3, 3:42 PM MST | Winter Weather Advisory | GJT | 58 hr |
| Jan 7, 4:09 PM MST | Winter Storm Warning | GJT | 65 hr |
| Jan 10, 3:21 PM MST | Winter Weather Advisory | GJT | 42 hr |
| Jan 12, 11:24 AM MST | Winter Storm Warning | GJT | 54 hr |
| Jan 18, 3:41 PM MST | Winter Storm Watch | GJT | 6 hr |
| Jan 18, 3:41 PM MST | Winter Storm Warning | GJT | 4 days |
| Jan 18, 3:41 PM MST | Winter Weather Advisory | GJT | 4 days |
| Jan 21, 7:48 PM MST | Winter Storm Watch | GJT | 16 hr |
| Jan 22, 4:30 AM MST | Winter Storm Warning | GJT | 72 hr |
| Jan 22, 4:30 AM MST | Winter Weather Advisory | GJT | 3 days |
| Feb 4, 3:45 PM MST | Winter Storm Watch | GJT | 23 hr |
| Feb 5, 3:03 PM MST | Winter Weather Advisory | GJT | 67 hr |
| Feb 10, 3:03 AM MST | Winter Weather Advisory | GJT | 4 days |
| Feb 17, 9:02 PM MST | Winter Weather Advisory | GJT | 53 hr |
| Feb 25, 8:55 PM MST | Winter Storm Watch | GJT | 19 hr |
| Feb 26, 3:26 PM MST | Winter Weather Advisory | GJT | 53 hr |
| Mar 4, 3:19 AM MST | Wind Advisory | GJT | 50 hr |
| Mar 22, 3:54 PM MDT | Winter Weather Advisory | GJT | 44 hr |
| Mar 26, 10:54 PM MDT | Winter Weather Advisory | GJT | 52 hr |
| Mar 30, 3:29 AM MDT | Winter Weather Advisory | GJT | 49 hr |
| Apr 7, 1:37 PM MDT | Wind Advisory | GJT | 33 hr |
| May 6, 2:32 PM MDT | Special Weather Statement | GJT | 43 min |
| May 6, 3:30 PM MDT | Mesoscale Discussion | SPC | 60 min |
| May 6, 3:41 PM MDT | Special Weather Statement | GJT | 49 min |
| May 9, 8:20 AM MDT | Severe Thunderstorm Warning | GJT | 25 min |
| May 9, 2:17 PM MDT | Special Weather Statement | GJT | 43 min |
| May 16, 3:55 AM MDT | Freeze Watch | GJT | 35 hr |
| Jun 6, 3:19 PM MDT | Fire Weather Watch | SLC | 11 hr |
| Jun 7, 2:46 AM MDT | Red Flag Warning | SLC | 5 days |
| Jun 7, 8:14 AM MDT | Red Flag Warning | SLC | 14 hr |
| Jun 7, 2:53 PM MDT | Fire Weather Watch | GJT | 24 hr |
| Jun 8, 3:01 PM MDT | Red Flag Warning | GJT | 4 days |
| Jun 9, 3:20 AM MDT | Fire Weather Watch | GJT | 10 hr |
| Jun 9, 2:56 PM MDT | Fire Weather Watch | SLC | 43 hr |
| Jun 10, 3:01 PM MDT | Red Flag Warning | SLC | 55 hr |
| Jun 11, 2:52 PM MDT | Wind Advisory | GJT | 28 hr |
| Jun 16, 4:02 AM MDT | Excessive Heat Watch | GJT | 48 hr |
| Jun 18, 3:56 AM MDT | Heat Advisory | GJT | 5 days |
| Jun 20, 3:09 PM MDT | Fire Weather Watch | SLC | 12 hr |
| Jun 21, 3:28 AM MDT | Red Flag Warning | SLC | 43 hr |
| Jun 21, 9:38 PM MDT | Red Flag Warning | GJT | 24 hr |
| Jun 24, 2:29 PM MDT | Red Flag Warning | SLC | 5 days |
| Jun 26, 2:52 PM MDT | Fire Weather Watch | GJT | 24 hr |
| Jun 26, 2:52 PM MDT | Red Flag Warning | GJT | 29 hr |
| Jun 27, 3:47 PM MDT | Red Flag Warning | GJT | 28 hr |
| Jun 28, 2:58 PM MDT | Red Flag Warning | GJT | 29 hr |
| Jul 5, 3:08 PM MDT | Red Flag Warning | SLC | 4 days |
| Jul 17, 1:43 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Jul 18, 2:32 PM MDT | Flash Flood Watch | GJT | 33 hr |
| Jul 19, 7:49 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Jul 20, 12:28 AM MDT | Flash Flood Warning | GJT | 3 hr |
| Jul 20, 4:05 AM MDT | Flash Flood Watch | GJT | 20 hr |
| Jul 21, 2:52 AM MDT | Flash Flood Watch | GJT | 21 hr |
| Jul 21, 1:14 PM MDT | Flash Flood Warning | SLC | 4 hr |
| Jul 21, 2:08 PM MDT | Flash Flood Warning | SLC | 6 hr |
| Jul 22, 4:51 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Jul 22, 4:57 PM MDT | Special Weather Statement | GJT | 48 min |
| Jul 22, 6:22 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Jul 24, 3:51 AM MDT | Flash Flood Watch | GJT | 44 hr |
| Jul 24, 6:56 PM MDT | Areal Flood Advisory | GJT | 5 hr |
| Jul 24, 7:11 PM MDT | Flash Flood Warning | GJT | 3 hr |
| Jul 24, 11:51 PM MDT | Areal Flood Advisory | GJT | 6 hr |
| Jul 25, 3:53 PM MDT | Areal Flood Advisory | GJT | 4 hr |
| Jul 25, 4:25 PM MDT | Special Weather Statement | GJT | 50 min |
| Jul 25, 4:55 PM MDT | Severe Thunderstorm Warning | GJT | 50 min |
| Jul 25, 5:37 PM MDT | Severe Thunderstorm Warning | GJT | 23 min |
| Jul 25, 6:00 PM MDT | Special Weather Statement | GJT | 30 min |
| Jul 25, 6:06 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Jul 26, 4:53 PM MDT | Special Weather Statement | GJT | 52 min |
| Jul 28, 2:17 AM MDT | Areal Flood Advisory | GJT | 3 hr |
| Jul 28, 2:58 PM MDT | Flash Flood Warning | SLC | 4 hr |
| Aug 6, 1:08 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Aug 6, 1:46 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Aug 12, 3:15 PM MDT | Severe Thunderstorm Warning | SLC | 30 min |
| Aug 24, 2:38 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Sep 14, 1:44 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Sep 14, 3:36 PM MDT | Special Weather Statement | GJT | 39 min |
| Sep 14, 4:10 PM MDT | Severe Thunderstorm Warning | GJT | 35 min |
| Sep 15, 3:37 PM MDT | Severe Thunderstorm Warning | GJT | 23 min |
| Sep 20, 3:11 PM MDT | Wind Advisory | GJT | 30 hr |
| Oct 7, 3:02 PM MDT | Red Flag Warning | SLC | 29 hr |
| Oct 13, 3:56 PM MDT | Freeze Watch | GJT | 11 hr |
| Oct 14, 3:03 AM MDT | Freeze Warning | GJT | 30 hr |
| Oct 20, 2:53 AM MDT | Wind Advisory | GJT | 16 hr |
| Nov 17, 4:11 AM MST | Wind Advisory | GJT | 17 hr |
| Dec 2, 8:39 PM MST | Wind Advisory | GJT | 26 hr |
| Dec 19, 4:10 PM MST | Winter Weather Advisory | GJT | 56 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 | 6 |
| Mesoscale Discussion | 2 |
| Special Weather Statement | 8 |
| Flooding | |
| Flash Flood Warning | 5 |
| Flash Flood Watch | 4 |
| Areal Flood Advisory | 12 |
| Winter | |
| Winter Storm Warning | 4 |
| Winter Storm Watch | 4 |
| Winter Weather Advisory | 12 |
| Heat | |
| Excessive Heat Watch | 1 |
| Heat Advisory | 1 |
| Cold | |
| Freeze Warning | 1 |
| Freeze Watch | 2 |
| Wind and dust | |
| Wind Advisory | 7 |
| Fire | |
| Red Flag Warning | 12 |
| Fire Weather Watch | 6 |
| 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 archive20162018
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.