This area's housing runs 1938 to 1993 with a median build year around 1970, and that matters for one reason: original torsion springs and steel components were engineered for a 20-to-25-year service life, which means a huge share of the doors across these 24 named areas are running on hardware well past its rated years. Layer on a severe cold climate band, and steel contracts, lubricant thickens, and springs that were already near the end of their wind cycle break under the extra tension cold puts on them. That's a different failure pattern than you'd get in a warmer market with newer stock - here, the fault is baked into the age of the house as much as the weather.
We don't have data on why any one specific spring failed on any one specific day - metal fatigue, a slightly bent track, a door that's been out of balance for months. What the numbers do tell us is that age-of-house plus cold is why this is a call we get, not an occasional one.