BOSTON — Rebekah Adelstone usually drives to work, which takes 15 minutes. Since record snows have fallen, she has not wanted to risk losing her precious parking spot, so she has taken a bus to the subway. But on Tuesday, after even more snow fell, the subway system was shut down. So she ended up taking two buses to work, and her commute stretched to two hours.

Her ordeal was typical of many residents, who soldiered through the more than six feet of snow that has piled up in the last 17 days. With no chance to melt, the snows have paralyzed this city, brought commerce to a near halt and sent roofs crashing down on numerous buildings, including a music store in Rockland, 30 miles southeast. Among the damaged goods was a $500,000 rhinestone-studded piano once owned by Liberace.

Most glaringly, the storms have exposed the vulnerabilities of the Massachusetts Bay Transportation Authority, which operates the region’s decrepit, fitful subways, buses and commuter rail lines. The underfunded system, which carries 1.3 million people a day and is $5.5 billion in debt, has been plagued in the last 17 days by breakdowns, fires, power losses, delays of two and three hours, and scenes of commuters having to disembark and pick their way along snow-covered tracks.

As the latest snowstorm bore down on Monday, the transit agency took commuters to work in the morning, but Gov. Charlie Baker declared a state of emergency in the afternoon, and officials shut down the system at 7 p.m., stranding — and infuriating — many who had no way to get home.