Alert archive / Montana / Big Horn County
Weather alerts in Big Horn County, Montana, 2021
115 weather alerts in 2021, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Big Horn County and its neighbors
Each county as a circle sized by its count in 2021. Tap one for its archive.
- Alerts
- 115
- Warnings
- 37
- Watches
- 20
- Advisories
- 25
- Busiest month
- July26 alerts
- Busiest day
- July 7, 20218 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Big Horn County, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 14 | 9 | 36% | 9 | 56% | 12 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Billings, MT: severe thunderstorm warnings | 51 | 23 | 55% | 84 | 42% | 18 min |
| NWS Billings, MT: flash flood warnings | 2 | 0 | 100% | 0 |
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 7, 5:23 PM MST | Winter Weather Advisory | BYZ | 16 hr |
| Jan 9, 6:15 AM MST | Special Weather Statement | BYZ | 2 hr |
| Jan 9, 8:16 AM MST | Special Weather Statement | BYZ | 89 min |
| Jan 9, 11:01 PM MST | Special Weather Statement | BYZ | 119 min |
| Jan 11, 3:04 AM MST | High Wind Watch | BYZ | 34 hr |
| Jan 12, 2:51 AM MST | High Wind Warning | BYZ | 65 hr |
| Jan 12, 12:06 PM MST | Winter Weather Advisory | BYZ | 39 hr |
| Jan 17, 2:47 AM MST | Winter Weather Advisory | BYZ | 33 hr |
| Feb 2, 1:20 AM MST | Winter Weather Advisory | BYZ | 43 hr |
| Feb 3, 2:50 PM MST | Winter Storm Watch | BYZ | 37 hr |
| Feb 4, 9:28 AM MST | Winter Storm Warning | BYZ | 3 days |
| Feb 6, 3:26 AM MST | Wind Chill Advisory | BYZ | 10 days |
| Feb 7, 3:48 AM MST | Winter Weather Advisory | BYZ | 24 hr |
| Feb 14, 2:24 AM MST | Winter Weather Advisory | BYZ | 48 hr |
| Feb 18, 6:30 AM MST | Special Weather Statement | BYZ | 75 min |
| Feb 18, 6:32 AM MST | Special Weather Statement | BYZ | 73 min |
| Feb 20, 3:00 AM MST | High Wind Warning | BYZ | 4 days |
| Feb 26, 2:33 PM MST | Winter Weather Advisory | BYZ | 28 hr |
| Mar 15, 12:43 PM MDT | Winter Weather Advisory | BYZ | 26 hr |
| Mar 24, 12:03 PM MDT | Winter Weather Advisory | BYZ | 63 hr |
| Mar 27, 3:15 AM MDT | High Wind Watch | BYZ | 23 hr |
| Mar 28, 2:27 AM MDT | High Wind Warning | BYZ | 40 hr |
| Mar 29, 7:29 AM MDT | Special Weather Statement | BYZ | 3 hr |
| Apr 4, 1:43 PM MDT | Winter Weather Advisory | BYZ | 49 hr |
| Apr 8, 2:29 AM MDT | Winter Weather Advisory | BYZ | 28 hr |
| Apr 14, 2:06 AM MDT | Winter Weather Advisory | BYZ | 58 hr |
| Apr 17, 2:09 AM MDT | Winter Storm Watch | BYZ | 13 hr |
| Apr 17, 3:31 PM MDT | Winter Storm Warning | BYZ | 45 hr |
| Apr 17, 3:31 PM MDT | Winter Weather Advisory | BYZ | 42 hr |
| Apr 22, 2:19 AM MDT | Winter Weather Advisory | BYZ | 32 hr |
| May 23, 10:42 AM MDT | Special Weather Statement | BYZ | 2 hr |
| May 28, 3:55 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 28, 4:51 PM MDT | Severe Thunderstorm Warning | BYZ | 24 min |
| May 28, 5:12 PM MDT | Severe Thunderstorm Warning | BYZ | 48 min |
| May 28, 5:59 PM MDT | Special Weather Statement | BYZ | 31 min |
| May 28, 6:29 PM MDT | Special Weather Statement | BYZ | 46 min |
| Jun 4, 4:44 PM MDT | Special Weather Statement | BYZ | 31 min |
| Jun 4, 5:12 PM MDT | Special Weather Statement | BYZ | 33 min |
| Jun 9, 3:19 AM MDT | High Wind Watch | BYZ | 24 hr |
| Jun 9, 3:57 AM MDT | Fire Weather Watch | BYZ | 10 hr |
| Jun 9, 1:38 PM MDT | Red Flag Warning | BYZ | 32 hr |
| Jun 10, 2:53 AM MDT | High Wind Warning | BYZ | 23 hr |
| Jun 13, 2:34 PM MDT | Excessive Heat Warning | BYZ | 54 hr |
| Jun 14, 9:26 AM MDT | Red Flag Warning | BYZ | 43 hr |
| Jun 18, 2:46 AM MDT | Fire Weather Watch | BYZ | 11 hr |
| Jun 18, 2:00 PM MDT | Red Flag Warning | BYZ | 31 hr |
| Jun 23, 4:33 PM MDT | Mesoscale Discussion | SPC | 117 min |
| Jun 29, 1:38 AM MDT | Excessive Heat Watch | BYZ | 36 hr |
| Jun 29, 2:27 PM MDT | Fire Weather Watch | BYZ | 23 hr |
| Jun 30, 1:34 PM MDT | Heat Advisory | BYZ | 4 days |
| Jun 30, 1:40 PM MDT | Red Flag Warning | BYZ | 31 hr |
| Jul 4, 4:09 PM MDT | Special Weather Statement | BYZ | 51 min |
| Jul 6, 2:37 PM MDT | Mesoscale Discussion | SPC | 83 min |
| Jul 6, 5:00 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 6, 5:55 PM MDT | Severe Thunderstorm Warning | BYZ | 50 min |
| Jul 6, 6:28 PM MDT | Severe Thunderstorm Warning | BYZ | 62 min |
| Jul 6, 6:42 PM MDT | Severe Thunderstorm Warning | BYZ | 63 min |
| Jul 6, 7:28 PM MDT | Severe Thunderstorm Warning | BYZ | 62 min |
| Jul 6, 8:21 PM MDT | Severe Thunderstorm Warning | BYZ | 54 min |
| Jul 6, 8:25 PM MDT | Severe Thunderstorm Warning | BYZ | 35 min |
| Jul 6, 9:00 PM MDT | Severe Thunderstorm Warning | BYZ | 32 min |
| Jul 7, 3:03 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 7, 5:48 PM MDT | Mesoscale Discussion | SPC | 117 min |
| Jul 7, 6:35 PM MDT | Severe Thunderstorm Warning | BYZ | 55 min |
| Jul 7, 7:24 PM MDT | Severe Thunderstorm Warning | BYZ | 66 min |
| Jul 7, 8:23 PM MDT | Severe Thunderstorm Warning | BYZ | 52 min |
| Jul 7, 9:13 PM MDT | Severe Thunderstorm Warning | BYZ | 62 min |
| Jul 9, 2:20 PM MDT | Mesoscale Discussion | SPC | 85 min |
| Jul 9, 4:12 PM MDT | Special Weather Statement | BYZ | 48 min |
| Jul 9, 4:50 PM MDT | Special Weather Statement | BYZ | 40 min |
| Jul 13, 2:21 PM MDT | Mesoscale Discussion | SPC | 84 min |
| Jul 14, 12:51 PM MDT | Excessive Heat Watch | BYZ | 46 hr |
| Jul 16, 11:06 AM MDT | Excessive Heat Warning | BYZ | 6 days |
| Jul 18, 2:06 AM MDT | Fire Weather Watch | BYZ | 13 hr |
| Jul 18, 3:10 PM MDT | Red Flag Warning | BYZ | 57 hr |
| Jul 24, 12:18 PM MDT | Excessive Heat Watch | BYZ | 25 hr |
| Jul 25, 1:39 PM MDT | Excessive Heat Warning | BYZ | 58 hr |
| Aug 7, 3:06 AM MDT | Fire Weather Watch | BYZ | 11 hr |
| Aug 7, 2:26 PM MDT | Red Flag Warning | BYZ | 34 hr |
| Aug 9, 2:58 AM MDT | Fire Weather Watch | BYZ | 10 hr |
| Aug 9, 12:55 PM MDT | Red Flag Warning | BYZ | 57 hr |
| Aug 14, 3:08 AM MDT | Fire Weather Watch | BYZ | 11 hr |
| Aug 14, 2:07 PM MDT | Red Flag Warning | BYZ | 3 days |
| Aug 15, 1:30 PM MDT | Heat Advisory | BYZ | 55 hr |
| Aug 16, 6:33 PM MDT | Special Weather Statement | BYZ | 42 min |
| Aug 16, 7:06 PM MDT | Special Weather Statement | BYZ | 39 min |
| Aug 17, 2:21 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Aug 26, 2:06 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Aug 26, 7:15 PM MDT | Special Weather Statement | BYZ | 30 min |
| Aug 26, 7:21 PM MDT | Severe Thunderstorm Warning | BYZ | 54 min |
| Aug 26, 8:22 PM MDT | Special Weather Statement | BYZ | 23 min |
| Aug 26, 9:02 PM MDT | Special Weather Statement | BYZ | 28 min |
| Aug 26, 9:27 PM MDT | Special Weather Statement | BYZ | 33 min |
| Sep 4, 2:20 PM MDT | Fire Weather Watch | BYZ | 24 hr |
| Sep 5, 2:29 PM MDT | Red Flag Warning | BYZ | 30 hr |
| Sep 14, 1:04 PM MDT | Red Flag Warning | BYZ | 31 hr |
| Sep 16, 1:53 PM MDT | Red Flag Warning | BYZ | 55 hr |
| Sep 27, 1:50 AM MDT | Fire Weather Watch | BYZ | 12 hr |
| Sep 27, 2:06 PM MDT | Red Flag Warning | BYZ | 31 hr |
| Oct 9, 1:08 PM MDT | Winter Storm Watch | BYZ | 38 hr |
| Oct 10, 2:47 PM MDT | Winter Storm Warning | BYZ | 3 days |
| Oct 11, 3:34 AM MDT | Winter Weather Advisory | BYZ | 47 hr |
| Nov 15, 2:44 AM MST | High Wind Warning | BYZ | 39 hr |
| Nov 24, 3:56 AM MST | Special Weather Statement | BYZ | 4 hr |
| Dec 4, 1:55 PM MST | Winter Weather Advisory | BYZ | 22 hr |
| Dec 6, 1:18 AM MST | Winter Weather Advisory | BYZ | 32 hr |
| Dec 13, 2:37 PM MST | Winter Weather Advisory | BYZ | 50 hr |
| Dec 18, 2:41 PM MST | Winter Weather Advisory | BYZ | 44 hr |
| Dec 25, 8:46 AM MST | Special Weather Statement | BYZ | 59 min |
| Dec 26, 4:06 AM MST | Winter Weather Advisory | BYZ | 17 hr |
| Dec 26, 4:59 AM MST | Special Weather Statement | BYZ | 3 hr |
| Dec 26, 8:00 AM MST | Special Weather Statement | BYZ | 90 min |
| Dec 26, 6:39 PM MST | Wind Chill Advisory | BYZ | 41 hr |
| Dec 27, 12:21 PM MST | Special Weather Statement | BYZ | 69 min |
| Dec 30, 12:30 PM MST | Winter Weather Advisory | BYZ | 27 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 | 14 |
| Severe Thunderstorm Watch | 2 |
| Mesoscale Discussion | 8 |
| Special Weather Statement | 25 |
| Winter | |
| Winter Storm Warning | 3 |
| Winter Storm Watch | 3 |
| Winter Weather Advisory | 21 |
| Heat | |
| Excessive Heat Warning | 3 |
| Excessive Heat Watch | 3 |
| Heat Advisory | 2 |
| Cold | |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| High Wind Warning | 5 |
| High Wind Watch | 3 |
| Fire | |
| Red Flag Warning | 12 |
| Fire Weather Watch | 9 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20202022
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.