An early Saturday morning explosion and fire on a lateral of the TransCanada Mainline in Manitoba left thousands without natural gas service amid freezing temperatures and prompted the closing of some schools in the region, according to pipeline notices and media reports.

At about 12:15 a.m. MST on Saturday, TransCanada experienced a fire on its Canadian Mainline on the Emerson lateral, south of Winnipeg, MB, which resulted in isolation of the affected pipeline, the pipeline told shippers in a notice.

"Efforts are being made to remedy the situation as soon as possible, but the duration of the outage is unknown at this time," TransCanada said in a customer notice.

Viking Gas Transmission issued an operational flow order (OFO) following the incident on Saturday because of the TransCanada outage. "Viking is currently receiving zero volumes at its Emerson interconnect with TransCanada Pipeline," it said.

However, at noon CST Monday Viking held a conference call with shippers during which it said operations were beginning to return to normal and gas was being received from TransCanada on one pipeline, although two other TransCanada lines feeding Viking -- one of them the ruptured line -- were still out of service.

Gas flow at the Emerson interconnect with TransCanada Pipeline had been restored; however, the gas flow and capacity levels had not yet returned to normal levels, Viking said at midday Monday.

The exact timing and amount of capacity that will become available remained unknown, but Viking anticipated having the ability to begin confirmation of nominations at Emerson during the ID1 cycle. The pipeline asked customers to begin a staged reinstatement of normal services immediately to allow a progressive normalization of the its system.

TransCanada did not respond to a request for more information.

Gas consumers in parts of Minnesota, Wisconsin and North Dakota, in addition to end-users in Manitoba, were asked to turn down their thermostats and conserve gas.

Earlier on Monday, Xcel Energy, one of the utilities served by Viking and affected by the TransCanada outage, said on its website that the situation was improving.

“Our system was stable overnight,” Excel said Monday morning. “We can see that natural gas flows are increasing from TransCanada pipeline into our pipeline service provider, Viking Gas Transmission. If this progress continues as we projected late yesterday, we expect to lift the conservation request later today [Monday].

“We want to see Viking stabilize and approach a more normal operation as well as ensure the stability of our system this morning. Then we believe we can handle an increase in demand on the system.”

Minnesota Energy Resources and its customers were also affected.

“One of the three natural gas pipelines affected by the incident in Canada is expected to return to normal operation sometime on Monday,” Minnesota Energy said on Sunday. “With the extreme cold weather heading our way and the time needed to bring the line to normal operation, we are asking our customers to continue to conserve.”

Among those losing gas services were residents of the town of Niverville, MB, which announced school closures due to the lack of gas service needed to keep buildings warm.

"TransCanada Pipe Line has opened a storefront information office to answer residents’ questions regarding natural gas services in our community and region. The office will be open to the public from 9:00 a.m. thru 9:00 p.m. each day until further notice," the town’s website said. "...In the event of a worst case scenario and the electrical grid fails, approximately 200 cots and blankets are being stored in the community. The Niverville Heritage Centre with its emergency support systems will serve as the shelter in place."

As many as 4,000 citizens were said to be without natural gas service, according to press reports, which also said that TransCanada had arranged for compressed natural gas to be trucked to hospitals and nursing homes to replace the lost pipeline gas supply. Temperatures in southern Manitoba Monday morning were 20 degrees below 0 F.

A Canadian Broadcasting Corp. report quoted a witness to the explosion as saying that flames shot 200-300 meters high from the ground. Canada's National Energy Board (NEB) reported no injuries; the fire was extinguished Saturday afternoon.

The NEB deployed its emergency response team, and TransCanada representatives were also on the scene, the NEB said on its website.