Alert archive / Montana / Severe Thunderstorm Warnings
Severe Thunderstorm Warnings in Montana, 2017
132 severe thunderstorm warnings in 2017. 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 2017. Tap one for its archive.
- Severe Thunderstorm Warnings
- 132
- Busiest month
- June46 severe thunderstorm warnings
- Busiest day
- July 10, 201713 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.
61 of 132 severe thunderstorm warnings covering Montana in 2017 had a qualifying storm report inside them; 104 of 219 hail, wind and damage reports fell inside a warning, on average 19 minutes after it went out.
Montana, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Severe thunderstorm warnings | 132 | 61 | 54% | 219 | 47% | 19 min |
Each office's whole area, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Missoula, MT: severe thunderstorm warnings | 13 | 8 | 38% | 24 | 38% | 20 min |
| NWS Great Falls, MT: severe thunderstorm warnings | 47 | 26 | 45% | 102 | 51% | 17 min |
| NWS Glasgow, MT: severe thunderstorm warnings | 42 | 12 | 71% | 43 | 42% | 22 min |
| NWS Billings, MT: severe thunderstorm warnings | 31 | 15 | 52% | 58 | 45% | 23 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 |
|---|---|---|---|---|
| Apr 23, 4:41 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Petroleum | 24 min |
| Apr 25, 6:56 PM MDT | Severe Thunderstorm Warning | TFX | Cascade | 19 min |
| May 6, 1:26 PM MDT | Severe Thunderstorm Warning | MSO | Ravalli | 34 min |
| May 6, 2:22 PM MDT | Severe Thunderstorm Warning | MSO | Deer Lodge, Granite | 23 min |
| May 6, 2:42 PM MDT | Severe Thunderstorm Warning | MSO | Deer Lodge, Granite | 33 min |
| May 6, 3:16 PM MDT | Severe Thunderstorm Warning | MSO | Powell | 29 min |
| May 6, 3:41 PM MDT | Severe Thunderstorm Warning | MSO | Powell | 34 min |
| May 6, 4:14 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 31 min |
| May 6, 4:45 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Lewis and Clark | 15 min |
| May 6, 4:59 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau, Lewis and Clark | 46 min |
| May 6, 5:44 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau, Judith Basin, Teton | 31 min |
| May 6, 6:14 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau, Pondera, Teton | 46 min |
| May 7, 3:17 PM MDT | Severe Thunderstorm Warning | BYZ | Sweet Grass | 28 min |
| May 7, 4:22 PM MDT | Severe Thunderstorm Warning | BYZ | Golden Valley, Stillwater | 23 min |
| May 7, 4:46 PM MDT | Severe Thunderstorm Warning | BYZ | Golden Valley, Musselshell, Stillwater, Yellowstone | 41 min |
| May 12, 3:30 PM MDT | Severe Thunderstorm Warning | TFX | Hill, Liberty | 30 min |
| May 12, 3:49 PM MDT | Severe Thunderstorm Warning | TFX | Hill, Liberty | 26 min |
| May 12, 4:03 PM MDT | Severe Thunderstorm Warning | TFX | Hill, Liberty | 27 min |
| May 12, 4:16 PM MDT | Severe Thunderstorm Warning | TFX | Hill, Liberty | 44 min |
| May 12, 4:51 PM MDT | Severe Thunderstorm Warning | TFX | Liberty, Toole | 39 min |
| May 12, 5:23 PM MDT | Severe Thunderstorm Warning | TFX | Hill, Liberty | 52 min |
| May 15, 6:05 PM MDT | Severe Thunderstorm Warning | BYZ | Custer | 25 min |
| May 15, 6:30 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 60 min |
| Jun 1, 3:29 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 31 min |
| Jun 1, 3:56 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Lewis and Clark | 49 min |
| Jun 1, 4:57 PM MDT | Severe Thunderstorm Warning | TFX | Cascade | 33 min |
| Jun 1, 5:29 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau | 61 min |
| Jun 1, 6:21 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 39 min |
| Jun 1, 6:53 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Petroleum, Phillips | 37 min |
| Jun 1, 6:58 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Hill | 47 min |
| Jun 4, 3:25 PM MDT | Severe Thunderstorm Warning | TFX | Cascade | 36 min |
| Jun 4, 4:18 PM MDT | Severe Thunderstorm Warning | TFX | Cascade | 27 min |
| Jun 4, 4:40 PM MDT | Severe Thunderstorm Warning | TFX | Cascade, Chouteau | 35 min |
| Jun 4, 5:11 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 34 min |
| Jun 4, 5:13 PM MDT | Severe Thunderstorm Warning | MSO | Missoula | 32 min |
| Jun 4, 5:13 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau | 32 min |
| Jun 4, 7:11 PM MDT | Severe Thunderstorm Warning | TFX | Glacier | 34 min |
| Jun 8, 4:37 PM MDT | Severe Thunderstorm Warning | MSO | Granite, Powell | 23 min |
| Jun 8, 4:57 PM MDT | Severe Thunderstorm Warning | MSO | Granite, Powell | 33 min |
| Jun 8, 5:36 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 24 min |
| Jun 8, 5:57 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark, Teton | 33 min |
| Jun 8, 6:10 PM MDT | Severe Thunderstorm Warning | TFX | Glacier, Pondera | 25 min |
| Jun 8, 6:37 PM MDT | Severe Thunderstorm Warning | TFX | Pondera, Toole | 38 min |
| Jun 8, 7:05 PM MDT | Severe Thunderstorm Warning | TFX | Glacier, Toole | 25 min |
| Jun 8, 7:13 PM MDT | Severe Thunderstorm Warning | TFX | Glacier, Pondera, Toole | 47 min |
| Jun 8, 7:49 PM MDT | Severe Thunderstorm Warning | TFX | Glacier, Liberty, Toole | 26 min |
| Jun 8, 8:14 PM MDT | Severe Thunderstorm Warning | TFX | Hill, Liberty, Toole | 46 min |
| Jun 8, 8:59 PM MDT | Severe Thunderstorm Warning | TFX | Blaine, Hill, Liberty | 46 min |
| Jun 8, 9:45 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Hill, Liberty | 45 min |
| Jun 8, 10:30 PM MDT | Severe Thunderstorm Warning | TFX | Hill | 30 min |
| Jun 9, 12:06 AM MDT | Severe Thunderstorm Warning | GGW | Phillips | 24 min |
| Jun 9, 12:55 AM MDT | Severe Thunderstorm Warning | GGW | Phillips | 35 min |
| Jun 12, 5:35 PM MDT | Severe Thunderstorm Warning | BYZ | Carbon | 25 min |
| Jun 12, 5:35 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 25 min |
| Jun 12, 5:57 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Carbon | 33 min |
| Jun 12, 6:25 PM MDT | Severe Thunderstorm Warning | BYZ | Carbon, Stillwater, Yellowstone | 65 min |
| Jun 12, 6:35 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Powder River | 25 min |
| Jun 12, 9:13 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 47 min |
| Jun 13, 5:18 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland | 57 min |
| Jun 13, 6:58 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Prairie | 47 min |
| Jun 20, 8:55 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud, Treasure | 65 min |
| Jun 20, 9:50 PM MDT | Severe Thunderstorm Warning | BYZ | Custer, Rosebud | 55 min |
| Jun 26, 5:02 PM MDT | Severe Thunderstorm Warning | TFX | Chouteau, Pondera, Teton | 43 min |
| Jun 27, 4:51 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Prairie | 54 min |
| Jun 27, 5:40 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone | 54 min |
| Jun 28, 1:31 PM MDT | Severe Thunderstorm Warning | GGW | McCone | 59 min |
| Jun 28, 1:38 PM MDT | Severe Thunderstorm Warning | TFX | Gallatin | 41 min |
| Jun 28, 2:10 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Richland | 47 min |
| Jun 28, 3:15 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Prairie | 60 min |
| Jul 6, 5:07 PM MDT | Severe Thunderstorm Warning | BYZ | Yellowstone | 38 min |
| Jul 6, 5:43 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Musselshell, Rosebud, Treasure, Yellowstone | 62 min |
| Jul 9, 4:05 PM MDT | Severe Thunderstorm Warning | BYZ | Carbon, Musselshell, Stillwater, Yellowstone | 55 min |
| Jul 9, 6:38 PM MDT | Severe Thunderstorm Warning | TFX | Broadwater, Jefferson, Lewis and Clark | 37 min |
| Jul 10, 3:08 PM MDT | Severe Thunderstorm Warning | TFX | Jefferson, Madison | 37 min |
| Jul 10, 3:12 PM MDT | Severe Thunderstorm Warning | MSO | Silver Bow | 33 min |
| Jul 10, 3:16 PM MDT | Severe Thunderstorm Warning | TFX | Beaverhead, Madison | 29 min |
| Jul 10, 4:13 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Phillips, Valley | 32 min |
| Jul 10, 4:16 PM MDT | Severe Thunderstorm Warning | MSO | Deer Lodge, Powell, Silver Bow | 29 min |
| Jul 10, 4:22 PM MDT | Severe Thunderstorm Warning | MSO | Silver Bow | 23 min |
| Jul 10, 4:40 PM MDT | Severe Thunderstorm Warning | TFX | Jefferson | 20 min |
| Jul 10, 4:43 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Garfield, McCone, Phillips, Roosevelt, Valley | 47 min |
| Jul 10, 4:52 PM MDT | Severe Thunderstorm Warning | BYZ | Custer, Rosebud | 23 min |
| Jul 10, 5:32 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Dawson, McCone, Roosevelt, Valley | 28 min |
| Jul 10, 5:41 PM MDT | Severe Thunderstorm Warning | BYZ | Custer | 49 min |
| Jul 10, 5:56 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Dawson, McCone, Richland, Roosevelt, Sheridan and 1 more | 42 min |
| Jul 10, 6:32 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Custer, Fallon | 73 min |
| Jul 10, 6:44 PM MDT | Severe Thunderstorm Warning | TFX | Lewis and Clark | 31 min |
| Jul 10, 7:32 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie, Richland, Wibaux | 35 min |
| Jul 11, 12:13 AM MDT | Severe Thunderstorm Warning | TFX | Blaine, Hill | 47 min |
| Jul 11, 1:00 AM MDT | Severe Thunderstorm Warning | TFX | Blaine | 45 min |
| Jul 11, 6:50 AM MDT | Severe Thunderstorm Warning | GGW | Roosevelt, Sheridan | 55 min |
| Jul 11, 5:03 PM MDT | Severe Thunderstorm Warning | GGW | Phillips, Valley | 57 min |
| Jul 11, 5:38 PM MDT | Severe Thunderstorm Warning | GGW | Valley | 67 min |
| Jul 11, 6:22 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Phillips, Valley | 53 min |
| Jul 11, 7:06 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Garfield, McCone | 54 min |
| Jul 11, 8:02 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, McCone, Richland | 44 min |
| Jul 15, 4:27 PM MDT | Severe Thunderstorm Warning | MSO | Missoula, Ravalli | 33 min |
| Jul 15, 4:59 PM MDT | Severe Thunderstorm Warning | MSO | Missoula, Ravalli | 46 min |
| Jul 16, 2:12 PM MDT | Severe Thunderstorm Warning | BYZ | Stillwater, Yellowstone | 48 min |
| Jul 16, 2:58 PM MDT | Severe Thunderstorm Warning | BYZ | Carbon, Stillwater, Sweet Grass, Yellowstone | 62 min |
| Jul 16, 5:03 PM MDT | Severe Thunderstorm Warning | GGW | Phillips, Valley | 27 min |
| Jul 16, 5:26 PM MDT | Severe Thunderstorm Warning | GGW | Phillips, Valley | 49 min |
| Jul 18, 4:36 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Powder River | 54 min |
| Jul 18, 5:24 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 66 min |
| Jul 19, 4:04 AM MDT | Severe Thunderstorm Warning | GGW | Dawson, Prairie, Wibaux | 26 min |
| Jul 19, 5:44 AM MDT | Severe Thunderstorm Warning | GGW | McCone, Prairie | 34 min |
| Jul 19, 6:08 AM MDT | Severe Thunderstorm Warning | GGW | Dawson, Wibaux | 52 min |
| Jul 20, 2:14 PM MDT | Severe Thunderstorm Warning | GGW | Richland | 19 min |
| Jul 27, 6:30 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 60 min |
| Jul 28, 6:38 PM MDT | Severe Thunderstorm Warning | GGW | Sheridan | 30 min |
| Jul 28, 7:03 PM MDT | Severe Thunderstorm Warning | GGW | Daniels | 28 min |
| Jul 29, 6:08 PM MDT | Severe Thunderstorm Warning | GGW | Sheridan | 52 min |
| Aug 1, 4:30 PM MDT | Severe Thunderstorm Warning | BYZ | Powder River | 33 min |
| Aug 1, 6:31 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 59 min |
| Aug 1, 7:11 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Petroleum | 64 min |
| Aug 1, 7:14 PM MDT | Severe Thunderstorm Warning | TFX | Fergus | 46 min |
| Aug 1, 8:08 PM MDT | Severe Thunderstorm Warning | GGW | Petroleum | 52 min |
| Aug 1, 8:47 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Carbon | 58 min |
| Aug 1, 9:02 PM MDT | Severe Thunderstorm Warning | BYZ | Musselshell | 28 min |
| Aug 1, 9:14 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud, Treasure, Yellowstone | 61 min |
| Aug 1, 10:00 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud, Treasure, Yellowstone | 43 min |
| Aug 1, 10:40 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn | 65 min |
| Aug 11, 5:19 PM MDT | Severe Thunderstorm Warning | GGW | Dawson, Richland | 56 min |
| Aug 11, 6:12 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Wibaux | 63 min |
| Aug 11, 7:18 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Wibaux | 27 min |
| Aug 12, 3:05 PM MDT | Severe Thunderstorm Warning | GGW | Prairie | 23 min |
| Aug 13, 8:06 PM MDT | Severe Thunderstorm Warning | TFX | Blaine, Hill | 39 min |
| Aug 24, 8:26 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Valley | 34 min |
| Aug 24, 8:52 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Phillips, Valley | 53 min |
| Aug 24, 9:40 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Roosevelt, Valley | 65 min |
| Aug 31, 4:52 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Roosevelt, Sheridan | 53 min |
| Aug 31, 7:01 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Roosevelt, Sheridan | 59 min |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- McCone County14
- Garfield County12
- Hill County12
- Valley County12
- Cascade County11
- Dawson County11
- Richland County11
- Lewis and Clark County10
- Chouteau County10
- Liberty County10
- Phillips County10
- Yellowstone County9
- Big Horn County9
- Prairie County7
- Roosevelt County7
- Stillwater County6
- Toole County6
- Carbon County6
- Rosebud County6
- Sheridan County6
- Powell County5
- Pondera County5
- Custer County5
- Glacier County5
- Daniels County5
- Wibaux County5
- Petroleum County4
- Granite County4
- Teton County4
- Musselshell County4
- Carter County4
- Blaine County4
- Treasure County4
- Ravalli County3
- Deer Lodge County3
- Missoula County3
- Powder River County3
- Jefferson County3
- Silver Bow County3
- Sweet Grass County2
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe 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.