By State › Montana
Montana: Risks & Trends
Download all of Montana as PDF PrintSame standard as every other page on this site: every figure below is independently sourced, and figures that vary across sources, or measure genuinely different things, are flagged as such rather than collapsed into one number that looks more precise than the underlying data actually supports.
The 1959 Hebgen Lake earthquake
| Metric | Figure |
|---|---|
| Date | August 17, 1959, 11:37 PM MST |
| Magnitude | 7.3 |
| Epicenter | ~6.5 mi WNW of West Yellowstone, MT |
| Landslide volume | ~50 million cubic yards of rock and debris |
| Deaths | 28, most at Rock Creek campground, buried by the slide |
| Bodies never recovered | 19, presumed buried beneath the slide debris |
| New feature created | Earthquake Lake ('Quake Lake'), formed when the slide dammed the Madison River |
| Historical ranking | Deadliest and most severe earthquake on record in Montana and the Intermountain West |
A dam that formed in a single night
Earthquake Lake didn’t exist before August 17, 1959; a landslide triggered by the quake dammed the Madison River in a matter of minutes. It’s a striking reminder that seismic events can reshape a landscape’s water features permanently and immediately, not just damage buildings.
The 2017 Lolo Peak fire
| Metric | Figure |
|---|---|
| Start date | July 15, 2017 |
| Cause | Lightning |
| Area burned | 53,902 acres |
| Deaths | 1 (firefighter Brent Witham) |
| Injuries | 1 non-fatal |
| Homes destroyed | 2 |
| Residences threatened | 1,150 |
| People evacuated | 3,000+ |
| Damage | $34.6 million |
Part of a broader, worse season
The Rice Ridge fire, burning the same summer northeast of Seeley Lake, grew from 40,000 to over 100,000 acres in a single week in September 2017 and became the nation’s top wildfire priority at the time, ultimately burning 155,900 acres. Lolo Peak wasn’t an isolated event; it was one part of one of Montana’s worst wildfire seasons in decades.