Weather alerts in Montana, 2024
2,511 weather alerts in 2024, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered any part of the state, so the counties below add up to more than the state.
Weather alerts by county
Each county as a circle sized by its count in 2024. Tap one for its archive.
- Alerts
- 2,511
- Warnings
- 535
- Watches
- 161
- Advisories
- 360
- Busiest month
- August673 alerts
- Busiest day
- August 19, 202491 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
3 of 8 tornado warnings covering Montana in 2024 had a tornado report inside them; 3 of 3 tornado reports fell inside a warning, on average 23 minutes after it went out.
Montana, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 8 | 3 | 63% | 3 | 100% | 23 min |
| Severe thunderstorm warnings | 343 | 146 | 57% | 512 | 59% | 24 min |
| Flash flood warnings | 3 | 0 | 100% | 3 | 0% |
Each office's whole area, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Great Falls, MT: severe thunderstorm warnings | 139 | 54 | 61% | 152 | 57% | 19 min |
| NWS Great Falls, MT: flash flood warnings | 2 | 0 | 100% | 1 | 0% | |
| NWS Billings, MT: tornado warnings | 1 | 0 | 100% | 0 | ||
| NWS Billings, MT: severe thunderstorm warnings | 89 | 31 | 65% | 127 | 50% | 23 min |
| NWS Missoula, MT: severe thunderstorm warnings | 32 | 19 | 41% | 108 | 44% | 15 min |
| NWS Missoula, MT: flash flood warnings | 4 | 0 | 100% | 2 | 0% | |
| NWS Glasgow, MT: tornado warnings | 7 | 3 | 57% | 3 | 100% | 23 min |
| NWS Glasgow, MT: severe thunderstorm warnings | 92 | 47 | 49% | 157 | 73% | 31 min |
| NWS Glasgow, MT: flash flood warnings | 0 | 1 | 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
2,511 alerts are too many to list on one page. Narrow it to a product above, to a month in the chart, or to a county.
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Valley County213
- Lewis and Clark County194
- McCone County190
- Phillips County189
- Garfield County183
- Chouteau County182
- Madison County177
- Pondera County176
- Judith Basin County176
- Gallatin County168
- Beaverhead County167
- Cascade County164
- Missoula County163
- Blaine County163
- Fergus County163
- Sweet Grass County160
- Glacier County158
- Stillwater County156
- Teton County151
- Roosevelt County150
- Richland County149
- Park County140
- Hill County140
- Big Horn County138
- Ravalli County137
- Meagher County137
- Dawson County135
- Petroleum County135
- Toole County134
- Rosebud County131
- Flathead County130
- Carter County129
- Daniels County129
- Broadwater County127
- Prairie County121
- Sheridan County121
- Lake County119
- Carbon County119
- Yellowstone County119
- Granite County118
16 more counties
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20232025
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.