Water and sewer crews are responding to a water main break on Fredericton's south side on Thursday.

On Twitter, the city said Fredericton Transit is being rerouted from Parkside Drive, near Prospect and Smythe  streets, because of the break. 

The alert came shortly after 11 a.m. 

"Buses will detour on Prospect into Greensfield and cover as much of the bus route as they can," the city said on social media.

Weather could be a factor

water main break

The break was pinpointed Thursday morning on Parkside Drive, close to Smythe Street. Parkside is now closed to traffic. (Maria Jose Burgos/CBC News)

Scott Grasman, assistant manager of Fredericton's water and sewer division, said the break represented a significant loss of water and was likely caused by a dramatic change in temperatures.

"It's very difficult to say for certain," he said. "This time of the year we've had a fairly significant stretch of cold weather, where a lot of frost has penetrated into the ground." 

And when there isn't any snow on the roads as insulation, Grasman said it can drive frost down even further.

"When you combine that with changes in temperature, that can cause the ground to shift along with older pipe," he said. "That can cause the pipe to fail." 

Grasman said city crews have been looking for a leak in that particular area since Wednesday afternoon. 

"The consumption numbers were showing that it looked like we were losing some water in that area," he said. "We had been doing some leak detection activity … and were finally able to pinpoint this particular location earlier this morning."  

water main break

Crews are hoping to finish repairs by the end of the day. (Maria Jose Burgos/CBC News)

Grasman expects repairs to last between five and six hours and hopes the break will be fixed before dark. But he said crews won't know what's required until the pipe is exposed.

"We will have [traffic] rerouted for as long as we are out in the middle of the road digging," he said.