Nearly a dozen cars and their parts lined Firestone Complete Auto Care in downtown Minneapolis.

On the ground lay a tire with a pothole-induced scrape across its surface, something manager Rich Fellers said the shop sees daily. Nearby was a BMW wheel with a rarer, more costly pothole casualty: a thin crack through the rim.

So begins pothole season in Minnesota — a nightmare for drivers, but a boon for the auto repair business.

At shops across the city, employees agreed that potholes are unusually rough this year. Not only are more cars coming in for repairs, but the rush started earlier.

Fellers said he started seeing cars with pothole damage at the beginning of March, about a month earlier than usual.

The story is similar elsewhere. John Grausam, owner of Lowry Repair Center in northeast Minneapolis, said March is typically slow. But he estimated a 40 percent increase in business last month, compared with the same time last year.

In addition to wheel and tire damage, vehicles hitting potholes can experience worn shocks and struts, damage to the suspension, exhaust system or engine, and steering misalignment.

While the number of customers with pothole damage typically drops off in late spring or early summer, some damage can cause long-term problems. Suspensions, for example, can fail later in the year if they're damaged by a pothole in the spring, Fellers said.

In addition to the increase in business from pothole damage, some shops are seeing worse damage than usual. Employees blame the unusually tough winter.

James Savoren, owner of Savoren Service North in north Minneapolis, said damage this year is the worst he has seen.

"It just seems more aggressive," he said.

Emma Nelson is a University of Minnesota student reporter on assignment for the Star Tribune.