Alert archive / Utah / San Juan County
Weather alerts in San Juan County, Utah, 2018
79 weather alerts in 2018, 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 2018. Tap one for its archive.
- Alerts
- 79
- Warnings
- 38
- Watches
- 13
- Advisories
- 25
- Busiest month
- June21 alerts
- Busiest day
- June 7, 20184 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, 2018
| 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 | 7 | 2 | 71% | 2 | 50% | 33 min |
Each office's whole area, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Salt Lake City, UT: tornado warnings | 0 | 2 | 0% | |||
| NWS Salt Lake City, UT: severe thunderstorm warnings | 46 | 6 | 87% | 38 | 39% | 19 min |
| NWS Salt Lake City, UT: flash flood warnings | 71 | 18 | 75% | 41 | 54% | 80 min |
| NWS Grand Junction, CO: tornado warnings | 0 | 1 | 0% | |||
| NWS Grand Junction, CO: severe thunderstorm warnings | 29 | 8 | 72% | 41 | 22% | 21 min |
| NWS Grand Junction, CO: flash flood warnings | 32 | 11 | 66% | 31 | 45% | 95 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, 2:55 PM MST | Winter Weather Advisory | GJT | 42 hr |
| Jan 8, 2:52 PM MST | Winter Storm Watch | GJT | 6 hr |
| Jan 8, 9:00 PM MST | Winter Storm Warning | GJT | 48 hr |
| Jan 19, 2:54 PM MST | Winter Weather Advisory | GJT | 54 hr |
| Feb 14, 3:39 AM MST | Winter Weather Advisory | GJT | 44 hr |
| Feb 17, 2:12 PM MST | Winter Weather Advisory | GJT | 66 hr |
| Feb 17, 2:13 PM MST | Wind Advisory | GJT | 27 hr |
| Feb 18, 1:25 PM MST | Wind Advisory | GJT | 30 hr |
| Feb 22, 3:10 PM MST | Winter Weather Advisory | GJT | 45 hr |
| Mar 3, 1:57 AM MST | Wind Advisory | GJT | 16 hr |
| Mar 16, 9:11 PM MDT | Winter Weather Advisory | GJT | 63 hr |
| Apr 11, 5:05 PM MDT | Wind Advisory | GJT | 27 hr |
| Apr 12, 2:09 PM MDT | Freeze Watch | GJT | 22 hr |
| Apr 13, 4:03 AM MDT | Freeze Warning | GJT | 28 hr |
| Apr 15, 1:50 PM MDT | Wind Advisory | GJT | 54 hr |
| Apr 17, 2:42 AM MDT | Freeze Warning | GJT | 30 hr |
| May 11, 8:47 PM MDT | Wind Advisory | GJT | 23 hr |
| May 25, 1:52 AM MDT | Red Flag Warning | GJT | 44 hr |
| May 29, 2:32 PM MDT | Red Flag Warning | SLC | 55 hr |
| May 29, 2:57 PM MDT | Fire Weather Watch | GJT | 24 hr |
| May 30, 4:30 AM MDT | Red Flag Warning | GJT | 42 hr |
| Jun 7, 3:34 AM MDT | Fire Weather Watch | SLC | 12 hr |
| Jun 7, 4:01 AM MDT | Fire Weather Watch | GJT | 24 hr |
| Jun 7, 2:40 PM MDT | Fire Weather Watch | GJT | 20 hr |
| Jun 7, 3:10 PM MDT | Red Flag Warning | SLC | 3 days |
| Jun 8, 4:20 AM MDT | Red Flag Warning | GJT | 41 hr |
| Jun 8, 10:50 AM MDT | Red Flag Warning | GJT | 59 hr |
| Jun 12, 3:00 PM MDT | Fire Weather Watch | GJT | 12 hr |
| Jun 12, 3:03 PM MDT | Red Flag Warning | SLC | 3 days |
| Jun 13, 3:02 AM MDT | Red Flag Warning | GJT | 42 hr |
| Jun 14, 3:48 AM MDT | Red Flag Warning | GJT | 41 hr |
| Jun 16, 11:50 PM MDT | Red Flag Warning | SLC | 22 hr |
| Jun 20, 3:09 PM MDT | Red Flag Warning | SLC | 3 days |
| Jun 21, 2:25 PM MDT | Red Flag Warning | GJT | 31 hr |
| Jun 21, 2:50 PM MDT | Red Flag Warning | SLC | 56 hr |
| Jun 22, 4:13 AM MDT | Fire Weather Watch | GJT | 11 hr |
| Jun 22, 3:14 PM MDT | Red Flag Warning | GJT | 30 hr |
| Jun 26, 12:58 PM MDT | Red Flag Warning | SLC | 4 days |
| Jun 26, 2:41 PM MDT | Fire Weather Watch | GJT | 14 hr |
| Jun 27, 4:43 AM MDT | Red Flag Warning | GJT | 41 hr |
| Jun 27, 2:34 PM MDT | Fire Weather Watch | GJT | 13 hr |
| Jun 28, 3:54 AM MDT | Red Flag Warning | GJT | 41 hr |
| Jul 1, 2:30 PM MDT | Red Flag Warning | SLC | 4 days |
| Jul 13, 5:31 PM MDT | Areal Flood Advisory | GJT | 104 min |
| Jul 13, 5:41 PM MDT | Flash Flood Warning | SLC | 5 hr |
| Jul 13, 6:15 PM MDT | Areal Flood Advisory | GJT | 2 hr |
| Jul 13, 10:44 PM MDT | Flash Flood Warning | SLC | 2 hr |
| Jul 14, 5:44 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Jul 14, 7:05 PM MDT | Flash Flood Warning | GJT | 3 hr |
| Jul 14, 8:27 PM MDT | Flash Flood Warning | GJT | 3 hr |
| Jul 16, 4:55 PM MDT | Flash Flood Warning | SLC | 3 hr |
| Jul 16, 6:02 PM MDT | Areal Flood Advisory | GJT | 2 hr |
| Jul 16, 7:07 PM MDT | Areal Flood Advisory | GJT | 113 min |
| Jul 19, 2:19 PM MDT | Flash Flood Warning | SLC | 8 hr |
| Jul 24, 4:25 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Aug 12, 7:42 PM MDT | Special Weather Statement | GJT | 48 min |
| Aug 21, 2:14 PM MDT | Special Weather Statement | GJT | 46 min |
| Aug 21, 2:39 PM MDT | Flash Flood Warning | SLC | 3 hr |
| Aug 25, 2:48 PM MDT | Areal Flood Advisory | GJT | 3 hr |
| Aug 29, 11:42 AM MDT | Red Flag Warning | GJT | 32 hr |
| Sep 10, 1:19 PM MDT | Red Flag Warning | SLC | 5 days |
| Sep 10, 1:38 PM MDT | Red Flag Warning | GJT | 55 hr |
| Sep 11, 2:32 PM MDT | Red Flag Warning | GJT | 54 hr |
| Sep 14, 2:07 AM MDT | Fire Weather Watch | SLC | 12 hr |
| Sep 14, 2:33 PM MDT | Red Flag Warning | SLC | 31 hr |
| Sep 17, 12:46 PM MDT | Red Flag Warning | SLC | 3 days |
| Sep 28, 3:24 AM MDT | Red Flag Warning | SLC | 66 hr |
| Sep 30, 2:58 PM MDT | Flash Flood Watch | GJT | 54 hr |
| Oct 4, 7:35 AM MDT | Special Weather Statement | GJT | 40 min |
| Oct 12, 1:29 PM MDT | Freeze Watch | GJT | 47 hr |
| Oct 14, 12:46 PM MDT | Freeze Warning | GJT | 22 hr |
| Nov 28, 3:03 PM MST | Winter Weather Advisory | GJT | 69 hr |
| Dec 1, 2:32 PM MST | Winter Weather Advisory | GJT | 27 hr |
| Dec 12, 9:43 AM MST | Wind Advisory | GJT | 12 hr |
| Dec 24, 2:11 PM MST | Winter Storm Warning | GJT | 39 hr |
| Dec 24, 8:58 PM MST | Winter Weather Advisory | GJT | 45 hr |
| Dec 27, 2:51 AM MST | Winter Weather Advisory | GJT | 45 hr |
| Dec 30, 3:40 AM MST | Winter Weather Advisory | GJT | 61 hr |
| Dec 30, 3:24 PM MST | Winter Storm Warning | GJT | 50 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 | |
| Special Weather Statement | 3 |
| Flooding | |
| Flash Flood Warning | 7 |
| Flash Flood Watch | 1 |
| Areal Flood Advisory | 7 |
| Winter | |
| Winter Storm Warning | 3 |
| Winter Storm Watch | 1 |
| Winter Weather Advisory | 11 |
| Cold | |
| Freeze Warning | 3 |
| Freeze Watch | 2 |
| Wind and dust | |
| Wind Advisory | 7 |
| Fire | |
| Red Flag Warning | 25 |
| Fire Weather Watch | 9 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20172019
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.