Winter Crashes on Missoula-Area Roads, 2016 to 2025

What this means for winter driving around Missoula

• Half the crashes in deep winter happen on winter road surfaces. From December to February, 52% of Missoula County crashes were on ice or frost, snow or slush; in November it was 24.3% and in March 13.0%. 78% of all winter-surface crashes happened in those three months.
• December is the busiest month for crashes. Missoula County logged 2,871 crashes in Decembers over the ten years, 32% more than an average month from April to October.
• Most winter crashes are not serious, but some are. 17% of winter-surface crashes involved a recorded injury, against 26% on dry roads, and 1.3% killed or seriously injured someone, against 4.3%. Even so, 22 people died in Missoula County crashes on winter surfaces in these ten years.
• Winters differ a lot. Missoula County had 722 crashes on winter surfaces in 2019 and 294 in 2024. One hard month can make the year: December 2017 alone had 416 crashes.
• If you were hurt in a crash on a winter road, our guide to what to do after a car accident in Montana covers the first steps, and the Winter and Holiday Legal Guide collects the season's other questions.

Crashes on winter road surfaces: Missoula, Ravalli and Lake counties and Montana, 2016 to 2025

Ten years combined. Deaths = people killed in crashes on ice or frost, snow or slush. The CSV download splits each county's winter-surface crashes into ice or frost, snow and slush.

Missoula County crashes by month and road surface, 2016 to 2025

Crashes on winter road surfaces by year

Calendar years. Share = percent of all crashes in that county and year.

Missoula County crash severity by road surface, 2016 to 2025

Recorded injury = any severity other than no apparent injury or unknown. Crashes on other or unrecorded surfaces are not shown.

How we did this

We used the Montana Department of Transportation's crash database extract for 2016 to 2025 (crash and person tables, updated October 8, 2026, downloaded November 12, 2026). A crash counts as a winter-surface crash when its "Road Surface Condition" is Ice/Frost, Snow or Slush. Severity uses the crash table's severity field; deaths count people whose injury severity is recorded as fatal.

Months pool all ten years: "December" means every December from 2016 to 2025. Years are calendar years.

A second, separate script re-reads the original Excel files with a different reader and recomputes the headline figures, and checks the road-surface counts for Missoula, Ravalli and Lake counties against MDT's public crash map service, a separate MDT system.

Limits

• Road surface is what the officer recorded at the scene. It describes the road, not the cause of the crash: a crash on a snowy road may have had other causes, and the data cannot say that the surface caused it.
• The figures cover crashes reported to law enforcement. Minor crashes nobody reported are not in the data.
• MDT describes the file as a one-time extraction: crash locations have not been reviewed, and details may change as MDT staff analyze the data further.
• The data has no traffic counts, so it cannot say whether driving is riskier per mile in winter, only how many crashes happen and on what surface.
• Crash data is collected for safety analysis. Under federal law (23 U.S.C. 407), this crash data can't be discovered or admitted as evidence in court, or considered in a lawsuit for damages; it describes patterns only.