Missoula's housing stock across its named areas - Westside, Northside, the University District, Lower and Upper Rattlesnake, Grant Creek, Franklin to the Fort, Miller Creek, and the rest - is mostly 1980s and 90s construction. That generation of garage doors was built with steel torsion springs and chain or belt-drive openers that were solid for their day, but they were engineered for a 15-20 year service life, not 40. At 30-plus years old, a spring has gone through tens of thousands of open-close cycles, and the steel is tired long before it looks tired.
The severe cold here makes that fatigue show up faster. Grease hardens below freezing, which increases the drag on rollers and hinges and puts extra load on a spring that's already near the end of its life. A door that opens stiffly in July will often bind or refuse to move at all on a sub-zero morning, because the motor or the torsion spring is fighting both age and temperature at the same time. This isn't unique to one neighborhood - it's the same story whether the house is three miles out in Orchard Homes or a couple miles east in the Heart of Missoula. The build era and the climate are doing the same thing to the hardware across the service area.