Northwestern Energy spokeswoman Claudia Rapkoch said heavy snow and falling branches dragged down power lines and cut electricity to several thousand customers, mostly along the Interstate 90 corridor between Bozeman and Billings.
The southernmost counties of Carbon, Park, Stillwater, Big Horn and Sweet Grass were hit particularly hard.
In one day, Cole Creek near the Red Lodge Mountain resort had received about 40 inches of snow.
Meanwhile, Nye in Stillwater County got about 20 inches of snow, and the Bighorn Mountains also saw high accumulations.
Between three and six inches of snow fell in Bozeman early October 5, cutting electricity to almost a thousand customers. By about 5 p.m., power had been restored to all major electricity lines.