Alert archive / Montana / Severe Thunderstorm Warnings
Severe Thunderstorm Warnings in Montana, 2009
295 severe thunderstorm warnings in 2009. An alert counts here when it covered any part of the state, so the counties below add up to more than the state. The archive of severe thunderstorm warnings reaches back to 1986.
Severe Thunderstorm Warnings by county
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Severe Thunderstorm Warnings
- 295
- Busiest month
- July151 severe thunderstorm warnings
- Busiest day
- July 6, 200933 severe thunderstorm warnings
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
125 of 295 severe thunderstorm warnings covering Montana in 2009 had a qualifying storm report inside them; 194 of 304 hail, wind and damage reports fell inside a warning, on average 24 minutes after it went out.
Montana, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Severe thunderstorm warnings | 295 | 125 | 58% | 304 | 64% | 24 min |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Missoula, MT: severe thunderstorm warnings | 30 | 13 | 57% | 35 | 80% | 22 min |
| NWS Great Falls, MT: severe thunderstorm warnings | 87 | 30 | 66% | 68 | 53% | 21 min |
| NWS Billings, MT: severe thunderstorm warnings | 85 | 28 | 67% | 63 | 60% | 23 min |
| NWS Glasgow, MT: severe thunderstorm warnings | 105 | 58 | 45% | 157 | 68% | 27 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 | Counties | Lasted |
|---|---|---|---|---|
| May 5, 3:12 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 33 min |
| May 5, 3:54 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Petroleum | 33 min |
| May 5, 4:56 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 64 min |
| May 7, 3:55 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Valley | 34 min |
| May 7, 7:49 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Hill | 35 min |
| May 8, 5:38 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 52 min |
| May 10, 12:21 PM MDT | Severe Thunderstorm Warning | GGW | Dawson | 9 min |
| May 10, 12:42 PM MDT | Severe Thunderstorm Warning | GGW | Dawson | 33 min |
| May 10, 12:57 PM MDT | Severe Thunderstorm Warning | GGW | Petroleum, Phillips | 48 min |
| May 10, 2:42 PM MDT | Severe Thunderstorm Warning | GGW | Roosevelt | 23 min |
| May 12, 2:11 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 64 min |
| May 12, 2:56 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 34 min |
| May 12, 5:57 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Yellowstone | 38 min |
| May 14, 6:10 PM MDT | Severe Thunderstorm Warning | GGW | McCone, Roosevelt, Valley | 48 min |
| May 19, 4:10 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Petroleum, Phillips | 47 min |
| May 19, 8:53 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Roosevelt, Valley | 67 min |
| May 19, 9:04 PM MDT | Severe Thunderstorm Warning | GGW | McCone, Richland, Roosevelt, Valley | 56 min |
| May 19, 10:00 PM MDT | Severe Thunderstorm Warning | GGW | Roosevelt, Sheridan | 30 min |
| May 30, 3:15 PM MDT | Severe Thunderstorm Warning | MSO | Flathead, Lake | 30 min |
| Jun 14, 4:47 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 58 min |
| Jun 15, 1:28 PM MDT | Severe Thunderstorm Warning | BYZ | Treasure, Yellowstone | 20 min |
| Jun 15, 4:00 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 30 min |
| Jun 20, 5:27 PM MDT | Severe Thunderstorm Warning | BYZ | Sweet Grass | 22 min |
| Jun 20, 7:47 PM MDT | Severe Thunderstorm Warning | GGW | McCone | 58 min |
| Jun 20, 9:59 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud | 31 min |
| Jun 20, 10:15 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 30 min |
| Jun 20, 10:44 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud | 31 min |
| Jun 25, 3:15 PM MDT | Severe Thunderstorm Warning | TFX | Blaine, Chouteau, Fergus | 45 min |
| Jun 25, 4:19 PM MDT | Severe Thunderstorm Warning | GGW | Phillips | 41 min |
| Jun 25, 4:39 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau, Judith Basin | 24 min |
| Jun 25, 6:07 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Valley | 23 min |
| Jun 25, 6:31 PM MDT | Severe Thunderstorm Warning | GGW | McCone, Roosevelt, Valley | 29 min |
| Jun 29, 5:28 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Sheridan | 62 min |
| Jun 29, 6:19 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Sheridan | 56 min |
| Jun 30, 2:55 PM MDT | Severe Thunderstorm Warning | TFX | Beaverhead, Madison | 65 min |
| Jun 30, 3:11 PM MDT | Severe Thunderstorm Warning | GGW | Richland | 49 min |
| Jun 30, 3:34 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 49 min |
| Jun 30, 3:56 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland | 64 min |
| Jun 30, 3:59 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Roosevelt | 61 min |
| Jun 30, 4:14 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie, Richland, Wibaux | 46 min |
| Jun 30, 4:37 PM MDT | Severe Thunderstorm Warning | TFX | Gallatin | 38 min |
| Jun 30, 5:06 PM MDT | Severe Thunderstorm Warning | GGW | Richland | 24 min |
| Jun 30, 5:33 PM MDT | Severe Thunderstorm Warning | GGW | Wibaux | 51 min |
| Jun 30, 5:57 PM MDT | Severe Thunderstorm Warning | GGW | Wibaux | 63 min |
| Jun 30, 6:11 PM MDT | Severe Thunderstorm Warning | BYZ | Fallon | 64 min |
| Jun 30, 6:32 PM MDT | Severe Thunderstorm Warning | BYZ | Fallon | 58 min |
| Jun 30, 7:04 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Fallon | 86 min |
| Jun 30, 8:40 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Fallon | 33 min |
| Jul 1, 5:23 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 52 min |
| Jul 2, 11:18 AM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 57 min |
| Jul 2, 11:23 AM MDT | Severe Thunderstorm Warning | BYZ | Rosebud | 43 min |
| Jul 2, 12:14 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 61 min |
| Jul 2, 1:04 PM MDT | Severe Thunderstorm Warning | BYZ | Custer, Rosebud | 30 min |
| Jul 2, 1:08 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud | 52 min |
| Jul 2, 1:49 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud | 40 min |
| Jul 2, 2:52 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Fergus | 53 min |
| Jul 2, 3:07 PM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Jefferson | 53 min |
| Jul 2, 3:11 PM MDT | Severe Thunderstorm Warning | TFX | Meagher | 64 min |
| Jul 2, 3:46 PM MDT | Severe Thunderstorm Warning | TFX | Blaine, Chouteau | 59 min |
| Jul 2, 3:57 PM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Gallatin | 63 min |
| Jul 2, 4:13 PM MDT | Severe Thunderstorm Warning | TFX | Meagher | 22 min |
| Jul 2, 4:16 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell | 59 min |
| Jul 2, 5:14 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell | 30 min |
| Jul 3, 4:17 PM MDT | Severe Thunderstorm Warning | BYZ | Yellowstone | 17 min |
| Jul 3, 4:37 PM MDT | Severe Thunderstorm Warning | GGW | Daniels | 53 min |
| Jul 3, 5:01 PM MDT | Severe Thunderstorm Warning | GGW | Phillips, Valley | 59 min |
| Jul 3, 5:27 PM MDT | Severe Thunderstorm Warning | GGW | Daniels | 63 min |
| Jul 3, 5:53 PM MDT | Severe Thunderstorm Warning | GGW | Valley | 67 min |
| Jul 3, 6:22 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Roosevelt | 53 min |
| Jul 3, 6:56 PM MDT | Severe Thunderstorm Warning | GGW | McCone, Roosevelt, Valley | 64 min |
| Jul 3, 7:57 PM MDT | Severe Thunderstorm Warning | GGW | McCone, Richland, Roosevelt, Valley | 63 min |
| Jul 3, 8:04 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Roosevelt | 56 min |
| Jul 3, 8:51 PM MDT | Severe Thunderstorm Warning | TFX | Blaine | 40 min |
| Jul 4, 2:29 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 30 min |
| Jul 4, 4:06 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 39 min |
| Jul 4, 4:23 PM MDT | Severe Thunderstorm Warning | TFX | Glacier | 37 min |
| Jul 4, 4:35 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Fergus | 40 min |
| Jul 4, 4:53 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 37 min |
| Jul 4, 5:21 PM MDT | Severe Thunderstorm Warning | TFX | Glacier, Pondera | 24 min |
| Jul 4, 5:29 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 5 min |
| Jul 4, 5:35 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 25 min |
| Jul 4, 5:46 PM MDT | Severe Thunderstorm Warning | TFX | Glacier, Pondera | 29 min |
| Jul 4, 6:16 PM MDT | Severe Thunderstorm Warning | TFX | Pondera | 59 min |
| Jul 4, 7:01 PM MDT | Severe Thunderstorm Warning | BYZ | Golden Valley, Musselshell, Stillwater, Yellowstone | 39 min |
| Jul 5, 3:41 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, McCone, Richland, Roosevelt, Valley | 64 min |
| Jul 5, 4:43 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Richland | 62 min |
| Jul 5, 5:43 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland | 62 min |
| Jul 5, 6:33 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Wibaux | 57 min |
| Jul 5, 7:00 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Wibaux | 60 min |
| Jul 5, 7:37 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie, Wibaux | 53 min |
| Jul 5, 8:20 PM MDT | Severe Thunderstorm Warning | BYZ | Fallon | 55 min |
| Jul 6, 12:56 PM MDT | Severe Thunderstorm Warning | MSO | Ravalli | 49 min |
| Jul 6, 1:37 PM MDT | Severe Thunderstorm Warning | MSO | Powell | 23 min |
| Jul 6, 1:45 PM MDT | Severe Thunderstorm Warning | MSO | Deer Lodge, Granite, Powell, Ravalli | 45 min |
| Jul 6, 2:06 PM MDT | Severe Thunderstorm Warning | TFX | Jefferson | 39 min |
| Jul 6, 2:07 PM MDT | Severe Thunderstorm Warning | MSO | Powell | 38 min |
| Jul 6, 2:12 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 48 min |
| Jul 6, 2:29 PM MDT | Severe Thunderstorm Warning | MSO | Granite, Powell | 46 min |
| Jul 6, 2:44 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark, Teton | 46 min |
| Jul 6, 2:49 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 41 min |
| Jul 6, 2:58 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 47 min |
| Jul 6, 3:03 PM MDT | Severe Thunderstorm Warning | MSO | Powell | 27 min |
| Jul 6, 3:03 PM MDT | Severe Thunderstorm Warning | TFX | Madison | 42 min |
| Jul 6, 3:06 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark, Teton | 54 min |
| Jul 6, 3:19 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Meagher | 41 min |
| Jul 6, 3:19 PM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Jefferson | 26 min |
| Jul 6, 3:33 PM MDT | Severe Thunderstorm Warning | TFX | Pondera, Teton | 42 min |
| Jul 6, 3:48 PM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Meagher | 17 min |
| Jul 6, 3:56 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Teton | 49 min |
| Jul 6, 3:58 PM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Meagher | 19 min |
| Jul 6, 4:09 PM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Cascade, Lewis and Clark, Meagher | 22 min |
| Jul 6, 4:15 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Judith Basin | 45 min |
| Jul 6, 4:21 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Fergus, Judith Basin | 39 min |
| Jul 6, 4:22 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Judith Basin | 3 min |
| Jul 6, 4:24 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau, Pondera, Teton | 38 min |
| Jul 6, 4:38 PM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Gallatin, Judith Basin, Meagher | 52 min |
| Jul 6, 4:44 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau | 46 min |
| Jul 6, 5:24 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 34 min |
| Jul 6, 5:43 PM MDT | Severe Thunderstorm Warning | BYZ | Wheatland | 62 min |
| Jul 6, 5:54 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Hill, Liberty | 51 min |
| Jul 6, 6:06 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 39 min |
| Jul 6, 7:40 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Petroleum, Phillips, Valley | 65 min |
| Jul 6, 7:57 PM MDT | Severe Thunderstorm Warning | GGW | Phillips | 63 min |
| Jul 6, 8:03 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 57 min |
| Jul 6, 8:43 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Phillips, Valley | 62 min |
| Jul 6, 9:36 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Garfield, McCone, Prairie, Roosevelt, Valley | 54 min |
| Jul 6, 9:44 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Roosevelt, Valley | 61 min |
| Jul 6, 10:28 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Prairie, Richland | 47 min |
| Jul 6, 10:43 PM MDT | Severe Thunderstorm Warning | GGW | Roosevelt, Sheridan | 62 min |
| Jul 6, 11:15 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland, Wibaux | 44 min |
| Jul 7, 7:13 PM MDT | Severe Thunderstorm Warning | BYZ | Golden Valley, Wheatland | 62 min |
| Jul 8, 6:52 AM MDT | Severe Thunderstorm Warning | TFX | Fergus | 38 min |
| Jul 8, 9:42 AM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone | 63 min |
| Jul 8, 10:41 AM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Richland | 64 min |
| Jul 8, 11:45 AM MDT | Severe Thunderstorm Warning | GGW | Richland | 60 min |
| Jul 8, 12:38 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Roosevelt | 22 min |
| Jul 8, 3:40 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 65 min |
| Jul 8, 4:29 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 26 min |
| Jul 8, 5:22 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 19 min |
| Jul 8, 5:56 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 29 min |
| Jul 8, 5:59 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Wibaux | 16 min |
| Jul 8, 6:18 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Fallon | 17 min |
| Jul 8, 6:39 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland | 29 min |
| Jul 8, 6:50 PM MDT | Severe Thunderstorm Warning | BYZ | Custer, Fallon | 55 min |
| Jul 12, 2:45 PM MDT | Severe Thunderstorm Warning | TFX | Madison | 25 min |
| Jul 12, 2:52 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Lewis and Clark | 38 min |
| Jul 12, 3:30 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau, Lewis and Clark, Teton | 45 min |
| Jul 12, 3:30 PM MDT | Severe Thunderstorm Warning | TFX | Madison | 32 min |
| Jul 12, 3:37 PM MDT | Severe Thunderstorm Warning | TFX | Gallatin | 38 min |
| Jul 12, 4:53 PM MDT | Severe Thunderstorm Warning | BYZ | Park, Sweet Grass | 25 min |
| Jul 12, 5:40 PM MDT | Severe Thunderstorm Warning | TFX | Madison | 50 min |
| Jul 12, 6:09 PM MDT | Severe Thunderstorm Warning | TFX | Hill, Liberty | 42 min |
| Jul 12, 6:13 PM MDT | Severe Thunderstorm Warning | TFX | Gallatin | 37 min |
| Jul 12, 6:31 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 59 min |
| Jul 12, 7:07 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 53 min |
| Jul 12, 7:58 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 62 min |
| Jul 12, 9:18 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud | 28 min |
| Jul 13, 10:19 AM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Cascade, Lewis and Clark, Meagher | 41 min |
| Jul 13, 10:56 AM MDT | Severe Thunderstorm Warning | TFX | Cascade | 22 min |
| Jul 13, 11:25 AM MDT | Severe Thunderstorm Warning | TFX | Pondera, Teton | 50 min |
| Jul 13, 11:52 AM MDT | Severe Thunderstorm Warning | TFX | Pondera | 38 min |
| Jul 13, 12:21 PM MDT | Severe Thunderstorm Warning | TFX | Pondera, Toole | 39 min |
| Jul 13, 1:04 PM MDT | Severe Thunderstorm Warning | TFX | Liberty, Toole | 41 min |
| Jul 13, 1:46 PM MDT | Severe Thunderstorm Warning | TFX | Liberty | 24 min |
| Jul 13, 2:29 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 44 min |
| Jul 13, 2:37 PM MDT | Severe Thunderstorm Warning | TFX | Blaine, Fergus | 38 min |
| Jul 13, 2:53 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Judith Basin, Meagher | 52 min |
| Jul 13, 2:53 PM MDT | Severe Thunderstorm Warning | TFX | Blaine | 52 min |
| Jul 13, 3:29 PM MDT | Severe Thunderstorm Warning | GGW | Phillips | 42 min |
| Jul 13, 4:01 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Powder River | 44 min |
| Jul 13, 4:09 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Petroleum, Phillips | 66 min |
| Jul 13, 4:53 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell | 37 min |
| Jul 13, 5:02 PM MDT | Severe Thunderstorm Warning | GGW | Phillips, Valley | 58 min |
| Jul 13, 5:09 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Valley | 66 min |
| Jul 13, 5:47 PM MDT | Severe Thunderstorm Warning | GGW | Valley | 58 min |
| Jul 13, 6:03 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone | 57 min |
| Jul 13, 6:32 PM MDT | Severe Thunderstorm Warning | GGW | Valley | 58 min |
| Jul 13, 6:57 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone | 63 min |
| Jul 13, 7:05 PM MDT | Severe Thunderstorm Warning | BYZ | Treasure | 55 min |
| Jul 13, 7:06 PM MDT | Severe Thunderstorm Warning | GGW | McCone, Roosevelt, Valley | 54 min |
| Jul 13, 7:43 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud | 54 min |
| Jul 15, 4:23 PM MDT | Severe Thunderstorm Warning | TFX | Pondera, Toole | 52 min |
| Jul 24, 3:22 PM MDT | Severe Thunderstorm Warning | TFX | Madison | 38 min |
| Jul 24, 5:13 PM MDT | Severe Thunderstorm Warning | MSO | Deer Lodge | 32 min |
| Jul 24, 5:37 PM MDT | Severe Thunderstorm Warning | MSO | Powell | 38 min |
| Jul 24, 5:43 PM MDT | Severe Thunderstorm Warning | MSO | Deer Lodge | 21 min |
| Jul 25, 5:57 PM MDT | Severe Thunderstorm Warning | TFX | Teton | 48 min |
| Jul 26, 1:44 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 35 min |
| Jul 26, 3:40 PM MDT | Severe Thunderstorm Warning | TFX | Teton | 39 min |
| Jul 26, 3:43 PM MDT | Severe Thunderstorm Warning | TFX | Blaine, Chouteau, Fergus | 47 min |
| Jul 26, 4:31 PM MDT | Severe Thunderstorm Warning | MSO | Granite | 44 min |
| Jul 26, 5:10 PM MDT | Severe Thunderstorm Warning | GGW | Phillips | 24 min |
| Jul 26, 5:20 PM MDT | Severe Thunderstorm Warning | MSO | Granite, Missoula | 40 min |
| Jul 26, 5:56 PM MDT | Severe Thunderstorm Warning | MSO | Granite, Missoula, Powell | 49 min |
| Jul 26, 6:01 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 21 min |
| Aug 4, 3:27 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 63 min |
| Aug 4, 3:56 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 64 min |
| Aug 4, 4:39 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Powder River | 36 min |
| Aug 4, 6:44 PM MDT | Severe Thunderstorm Warning | BYZ | Stillwater, Yellowstone | 31 min |
| Aug 4, 7:16 PM MDT | Severe Thunderstorm Warning | BYZ | Yellowstone | 29 min |
| Aug 5, 8:31 PM MDT | Severe Thunderstorm Warning | MSO | Flathead, Lincoln | 44 min |
| Aug 6, 1:04 PM MDT | Severe Thunderstorm Warning | TFX | Beaverhead | 41 min |
| Aug 6, 1:46 PM MDT | Severe Thunderstorm Warning | TFX | Beaverhead | 44 min |
| Aug 6, 1:54 PM MDT | Severe Thunderstorm Warning | MSO | Deer Lodge, Silver Bow | 51 min |
| Aug 6, 2:41 PM MDT | Severe Thunderstorm Warning | MSO | Deer Lodge, Silver Bow | 49 min |
| Aug 6, 2:50 PM MDT | Severe Thunderstorm Warning | TFX | Jefferson, Lewis and Clark | 55 min |
| Aug 6, 4:06 PM MDT | Severe Thunderstorm Warning | BYZ | Sweet Grass | 54 min |
| Aug 6, 4:19 PM MDT | Severe Thunderstorm Warning | MSO | Silver Bow | 36 min |
| Aug 6, 4:32 PM MDT | Severe Thunderstorm Warning | TFX | Meagher | 43 min |
| Aug 6, 5:00 PM MDT | Severe Thunderstorm Warning | BYZ | Stillwater, Sweet Grass | 60 min |
| Aug 6, 5:02 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Judith Basin, Meagher | 43 min |
| Aug 6, 5:12 PM MDT | Severe Thunderstorm Warning | TFX | Fergus, Judith Basin | 48 min |
| Aug 6, 5:19 PM MDT | Severe Thunderstorm Warning | TFX | Meagher | 41 min |
| Aug 6, 5:30 PM MDT | Severe Thunderstorm Warning | TFX | Gallatin, Meagher | 60 min |
| Aug 6, 5:59 PM MDT | Severe Thunderstorm Warning | BYZ | Stillwater | 61 min |
| Aug 6, 6:01 PM MDT | Severe Thunderstorm Warning | TFX | Fergus, Judith Basin | 44 min |
| Aug 6, 6:04 PM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Gallatin | 41 min |
| Aug 6, 6:41 PM MDT | Severe Thunderstorm Warning | TFX | Meagher | 28 min |
| Aug 6, 6:44 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 48 min |
| Aug 6, 6:55 PM MDT | Severe Thunderstorm Warning | GGW | Phillips | 65 min |
| Aug 6, 7:34 PM MDT | Severe Thunderstorm Warning | GGW | Petroleum | 56 min |
| Aug 6, 7:57 PM MDT | Severe Thunderstorm Warning | GGW | Phillips | 49 min |
| Aug 7, 7:02 AM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau, Teton | 18 min |
| Aug 7, 4:27 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 63 min |
| Aug 7, 5:00 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 30 min |
| Aug 7, 5:26 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud | 64 min |
| Aug 7, 5:35 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell, Yellowstone | 55 min |
| Aug 7, 5:47 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud | 58 min |
| Aug 7, 6:15 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell, Yellowstone | 60 min |
| Aug 7, 6:30 PM MDT | Severe Thunderstorm Warning | BYZ | Powder River, Rosebud | 60 min |
| Aug 7, 6:43 PM MDT | Severe Thunderstorm Warning | BYZ | Powder River, Rosebud | 62 min |
| Aug 7, 6:44 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 46 min |
| Aug 7, 7:16 PM MDT | Severe Thunderstorm Warning | BYZ | Powder River | 42 min |
| Aug 7, 7:23 PM MDT | Severe Thunderstorm Warning | BYZ | Custer | 52 min |
| Aug 7, 7:32 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud | 20 min |
| Aug 7, 7:41 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Custer, Powder River | 34 min |
| Aug 7, 7:46 PM MDT | Severe Thunderstorm Warning | BYZ | Powder River | 13 min |
| Aug 7, 8:05 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Custer, Fallon | 55 min |
| Aug 7, 8:45 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Fallon | 45 min |
| Aug 7, 8:46 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie, Wibaux | 37 min |
| Aug 7, 8:50 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 55 min |
| Aug 8, 5:01 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 48 min |
| Aug 13, 2:54 PM MDT | Severe Thunderstorm Warning | MSO | Ravalli | 21 min |
| Aug 13, 6:21 PM MDT | Severe Thunderstorm Warning | BYZ | Sweet Grass, Wheatland | 53 min |
| Aug 13, 8:20 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell | 53 min |
| Aug 13, 10:51 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie, Wibaux | 54 min |
| Aug 13, 11:47 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie, Richland, Wibaux | 58 min |
| Aug 14, 12:44 AM MDT | Severe Thunderstorm Warning | GGW | Richland | 32 min |
| Aug 14, 1:50 AM MDT | Severe Thunderstorm Warning | GGW | Richland, Roosevelt | 40 min |
| Aug 14, 2:32 AM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland | 28 min |
| Aug 14, 2:30 PM MDT | Severe Thunderstorm Warning | TFX | Gallatin | 18 min |
| Aug 14, 2:32 PM MDT | Severe Thunderstorm Warning | BYZ | Park | 52 min |
| Aug 14, 2:47 PM MDT | Severe Thunderstorm Warning | BYZ | Wheatland | 50 min |
| Aug 14, 7:05 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 55 min |
| Aug 14, 7:15 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell | 53 min |
| Aug 14, 7:27 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud | 52 min |
| Aug 14, 7:51 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud | 54 min |
| Aug 14, 7:59 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 61 min |
| Aug 14, 8:49 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone | 56 min |
| Aug 14, 9:08 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 51 min |
| Aug 14, 9:44 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Richland | 61 min |
| Aug 14, 10:44 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Richland | 61 min |
| Aug 14, 10:46 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Prairie | 49 min |
| Aug 14, 11:46 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland | 59 min |
| Aug 21, 6:31 PM MDT | Severe Thunderstorm Warning | MSO | Powell | 22 min |
| Aug 21, 6:37 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 38 min |
| Aug 21, 7:04 PM MDT | Severe Thunderstorm Warning | MSO | Granite, Powell | 41 min |
| Aug 21, 7:38 PM MDT | Severe Thunderstorm Warning | MSO | Granite, Powell | 37 min |
| Aug 21, 8:10 PM MDT | Severe Thunderstorm Warning | MSO | Granite, Powell | 50 min |
| Aug 22, 8:33 PM MDT | Severe Thunderstorm Warning | BYZ | Wheatland | 25 min |
| Aug 23, 7:40 PM MDT | Severe Thunderstorm Warning | GGW | McCone | 65 min |
| Aug 23, 8:02 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Richland | 58 min |
| Aug 23, 8:30 PM MDT | Severe Thunderstorm Warning | GGW | McCone, Roosevelt, Valley | 60 min |
| Aug 23, 8:59 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Richland, Roosevelt | 61 min |
| Aug 23, 9:28 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Roosevelt, Valley | 30 min |
| Aug 23, 9:34 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Richland | 56 min |
| Aug 23, 9:46 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Roosevelt | 59 min |
| Aug 23, 10:32 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland, Roosevelt | 41 min |
| Aug 23, 10:42 PM MDT | Severe Thunderstorm Warning | GGW | Richland | 33 min |
| Aug 23, 11:15 PM MDT | Severe Thunderstorm Warning | GGW | Richland | 45 min |
| Sep 6, 9:01 PM MDT | Severe Thunderstorm Warning | GGW | Phillips, Valley | 59 min |
| Sep 13, 5:16 PM MDT | Severe Thunderstorm Warning | BYZ | Custer | 29 min |
| Sep 13, 5:26 PM MDT | Severe Thunderstorm Warning | BYZ | Custer | 64 min |
| Sep 13, 5:28 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Prairie | 62 min |
| Sep 13, 6:12 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie | 63 min |
| Sep 13, 7:04 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie | 56 min |
| Sep 13, 7:08 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie, Wibaux | 52 min |
| Sep 13, 7:43 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Valley | 62 min |
| Sep 13, 7:52 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Wibaux | 37 min |
| Sep 13, 7:58 PM MDT | Severe Thunderstorm Warning | GGW | Dawson | 62 min |
| Sep 13, 8:53 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie | 67 min |
| Sep 13, 9:20 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland | 55 min |
| Sep 13, 10:11 PM MDT | Severe Thunderstorm Warning | GGW | Roosevelt, Valley | 64 min |
| Sep 13, 10:20 PM MDT | Severe Thunderstorm Warning | GGW | McCone | 55 min |
| Sep 14, 1:32 AM MDT | Severe Thunderstorm Warning | GGW | Daniels, Valley | 58 min |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Dawson County33
- Richland County33
- McCone County29
- Valley County26
- Roosevelt County24
- Big Horn County22
- Garfield County21
- Chouteau County20
- Carter County18
- Rosebud County15
- Phillips County14
- Cascade County14
- Meagher County14
- Fergus County13
- Prairie County13
- Wibaux County13
- Lewis and Clark County12
- Powell County11
- Daniels County10
- Teton County10
- Judith Basin County9
- Fallon County9
- Broadwater County9
- Pondera County9
- Yellowstone County8
- Gallatin County8
- Musselshell County8
- Granite County8
- Custer County7
- Powder River County7
- Petroleum County6
- Blaine County6
- Madison County6
- Sweet Grass County5
- Deer Lodge County5
- Wheatland County5
- Sheridan County4
- Jefferson County4
- Stillwater County4
- Liberty County4
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20082010
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.