PITTSFIELD — A water main near Hubbard and Dalton avenues that had been damaged last week by a state contractor burst Wednesday while crews readied the site for repairs, sending water and rocks into the air and damaging most vehicles that were parked at a nearby tire shop.

"It looked like it started raining," said Matt Buffoni, assistant manager of City Tire. "So, I stepped outside the office and I heard a sprinkle of rocks, if you will, and you could tell it was not just water coming down."

Buffoni said he rushed outside to check on his truck, finding a rear window smashed, but he stopped when "a 3-, 4-inch rock landed right in front of me."

"If I just tossed that at you and hit you in the head with it, it would knock you out cold. Imagine it being 50 feet in the air and coming down," he said.

The break was "directly related" to damage caused to the main Aug. 19, when a contractor hired by the Massachusetts Department of Transportation to install foundations for traffic signals drilled in the area and struck the waterline, the city said in a statement.

MassDOT spokeswoman Judith Reardon Riley said in an email that the waterline was "partially damaged" Aug. 19, during contractor Daigle Electric Co.'s "excavation operations." The contractor had called Dig-Safe, a not-for-profit that alerts utility companies when crews are digging, but a waterline was not marked at the location of the work site at Hubbard and Dalton avenues.

"The Public Utilities Department for the City of Pittsfield was contacted to facilitate a response to the damaged waterline. At that time, the City decided to backfill the excavation with stone to let the water bleed out until the City could organize a repair," she said.

The high-pressure water main supplies the city with water. At the scene Wednesday, Commissioner of Public Services and Utilities Ricardo Morales said crews had been at the site to repair the damage caused last week.

He said it appeared that the main burst as crews began clearing away the earth around the 2-foot-diameter pipe in order to make way for what those consulting on the repair project thought would be a simple fix.

"My educated guess is that exposing the ground made the pipe weaker at the break" that occurred last week, Morales said. But, to prepare for the worst, the city also purchased new length of pipe just in case the damaged section had to be replaced.

"This is the worst scenario we were anticipating," Morales said.

Witnesses said the burst water main sent water shooting 50 feet or more into the air, flinging rocks across the East Branch of the Housatonic River that landed in the crowded parking lot of City Tire.

"That's the length of a football field, and it was sending rocks that far," said tire and alignment specialist James Vinson.

Morales said water was cut after the pipe burst Wednesday. Water still was flowing out of the pipe and into the river just before 11 a.m., though the pressure had gone down considerably. Morales said he worried about the burst main depleting water levels in the Cleveland Reservoir.

The main blew amid statewide drought conditions and one day after the city had asked residents to voluntarily conserve water as part of Stage 1 of its water-management plan.

"My worry right now is that we were already in a Stage 1 drought, and that reservoir is going to just come down," Morales said. Because of the burst main, "we may be closing in faster than we anticipated to our next stage."

The city, in a statement, stressed the importance of conserving water and said the repairs were expected to be completed within 24 hours.

"We anticipate the repair will be completed within 24 hours at which point water pressures and availability will be back to normal, however, we are still under the voluntary restrictions for outdoor use according to our current State of Water Conservation," the statement said.

About 25 vehicles in the lot were damaged, ranging from dents to the exterior to shattered windows, according to Buffoni. He said rocks continued to fall in the area for over a half-hour.

"The rock shower was a solid 35 minutes," Buffoni said.

No one was injured, according to Morales and Finance Director Matt Kerwood.

"We're certainly thankful that no one did get hurt, because the possibility did exist, clearly," Kerwood said.

While a MassDOT contractor caused the initial damage to the water main last week, according to the city, Kerwood said the city's contractor is handling the repairs.

Kerwood said City Tire will be supplying the city with a list of damaged vehicles, and added that some owners of vehicles that were on the City Tire lot have begun contacting the city. He said the city and its insurer, MIIA Property and Casualty Group, will work with the vehicle owners toward covering the cost of fixing the damage.

"Ultimately, we the city will be responsible for paying for the damage, and we'll need to work with each individual on a case-by-case basis," he said.

Amanda Burke can be reached at aburke@berkshireeagle.com, on Twitter @amandaburkec and 413-496-6296.