ST. PIERRE-JOLYS, Man. - Several thousand people in southern Manitoba have been told that a pipeline explosion could mean they'll be without natural gas service for up to several days as temperatures hover close to —20 C.

"As far as the temperature is concerned, the words 'polar vortex' is what they're saying," Myron Dyck, a spokesman for the Town of Niverville, said on Saturday.

The explosion and fire at a TransCanada Pipelines valve site near St. Pierre-Jolys happened early Saturday morning, sending a massive fireball into the dark sky.

The flames were out by Saturday afternoon and there were no reported injuries.

But Manitoba Hydro said that in order to repair the line, TransCanada shut off its supply of natural gas for several municipalities affecting approximately 4,000 people.

The utility said it had no estimate from TransCanada about when service would be restored and that customers should prepare for the outage to last at least one day.

The temperature in Niverville on Saturday afternoon was —18 C and Environment Canada was calling for even colder temperatures on Sunday and Monday.

Dyck said people in the region use either gas and gas or electricity to heat their homes.

"We have contingency plans in place should this be for a greater time period," Dyck said when asked about what actions the town might take to assist residents without heat.

In the Rural Municipality of Hanover, a warming centre was being set up in a local church.

"For those who feel the need to leave their homes, we urge people to stay with friends or family with an alternative heat source," Hanover Emergency Coordinator Denis Vassart said on the community's website.

A Manitoba government spokesman said it wasn't known how many people had alternative heat sources such as space heaters or fireplaces.

TransCanada said it shut down the Emerson Lateral portion of the Canadian Mainline natural gas pipeline system due to the explosion and vented the remaining gas. It said trucks containing compressed natural gas were being sent to metering stations to provide gas to some critical services such as personal care homes and hospitals, as well as schools or churches being used as emergency warming centres.

TransCanada said in a news release that was working with Manitoba Hydro to restore regular natural gas service as quickly as possible.

Niverville Deputy Mayor John Funk said in a statement on the town's website that depending on the extent of the repairs, service is expected to be lost for minimum of 24 hours to multiple days.

Funk said Manitoba Hydro is asking residents to turn down thermostats and minimize use of electric heaters. He also urged caution when using all types of space heaters, and warned people not to use barbecues or any other unapproved heaters indoors that might produce carbon monoxide.

Five homes were evacuated as a result of the explosion and roads leading into the site were closed.

The Transportation Safety Board of Canada and the National Energy Board are investigating.

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  • This photo provided by Royal Canadian Mounted Police shows a natural gas pipeline fire on Saturday, Jan. 25, 2014 near Winnipeg. TransCanada says it has shut down the Emerson Lateral portion of the Canadian Mainline natural gas pipeline system and is venting the gas.

  • MORE: The Pros And Cons Of Natural Gas

  • Con: It Emits Carbon When Burned

    Natural gas isn’t completely different from oil or coal – it is still a fossil fuel, <a href="http://www.ucsusa.org/clean_energy/technology_and_impacts/energy_technologies/how-natural-gas-works.html#enviroimpacts" target="_hplink">emitting carbon and nitrogen oxides </a>(NOx) when it is burned and contributing to climate change and smog.

  • Pro: It’s The Cleanest Burning Fossil Fuel

    Compared to coal (even “clean coal”) and oil, natural gas is the cleanest fossil fuel, emitting half the amount of carbon compared to burning coal. Scientists and policy makers see it as a “<a href="http://www.scientificamerican.com/article.cfm?id=natural-gas-could-serve-as-bridge-fuel-to-low-carbon-future" target="_hplink">bridge</a>” to a low-carbon economy. Pictured: Chesapeake Energy Corp. CEO Aubrey McClendon speaks at the opening of a compressed natural gas filling station.

  • Pro: Some Carbon Could Be Removed

    A <a href="http://www.boston.com/business/technology/articles/2010/11/08/process_removes_carbon_yielding_cleaner_natural_gas/" target="_hplink">new process </a>could remove carbon from natural gas before it is burned, reducing emissions by as much as 40 percent. The by-product, carbon black, can be used in printer inks, tires, and other products. Atlantic Hydrogen Inc. of Fredericton, New Brunswick has partnered with the utility Nation Grid and is considering building a pilot plant.

  • Con: It Contaminates Local Water In A Scary Way

    The biggest reason for natural gas’s prominence in the news as of late is the controversial extraction process. Called fracking, it forces chemicals, sand and water down into the ground to fracture the shale and allow natural gas to flow freely. The documentary <a href="http://gaslandthemovie.com/whats-fracking" target="_hplink">Gasland</a> showcases the alleged consequences, with local water <a href="http://www.huffingtonpost.com/2010/09/06/mark-and-linda-wilfong-we_n_705011.html" target="_hplink">catching fire</a> right out of the tap. People across the country near fracking operations are <a href="http://www.npr.org/templates/story/story.php?storyId=104565793" target="_hplink">reporting</a> rashes from taking showers in the water, and livestock that won’t drink it, among other complaints. The EPA recently <a href="http://www.huffingtonpost.com/2010/11/09/epa-halliburton-subpoenae_n_781045.html" target="_hplink">subpoenaed Halliburton</a> to find out what chemicals are used in Fracking.

  • Pro: It’s Abundant In The United States

    Unlike oil, which has to largely be imported, gas is <a href="http://www.charlotteobserver.com/2010/10/15/1762520/sudden-abundance-of-natural-gas.html" target="_hplink">abundantly available</a>; especially since the full potential of <a href="http://www.dec.ny.gov/energy/46288.html" target="_hplink">Marcellus Shale</a>, a formation of shale extending from Ohio and West Virginia up to Pennsylvania and New York, has been discovered. It promises to bring the U.S. closer to energy independence.

  • Con: Its Extraction Damages The Immediate Surroundings

    <a href="http://www.ucsusa.org/clean_energy/technology_and_impacts/energy_technologies/how-natural-gas-works.html#enviroimpacts" target="_hplink">In order to get at</a> natural gas, land must be cleared and roads built for access to the well. Often wells are drilled in remote areas, requiring extensive infrastructure from scratch. Traffic to the well causes noise, dust, and pollutants.

  • Pro: It Has A Lot Of Potential Uses

    Its most prevalent use is for generation electricity, but natural gas also <a href="http://www.ucsusa.org/clean_energy/technology_and_impacts/energy_technologies/how-natural-gas-works.html#usesofng" target="_hplink">can be used </a>to heat homes and fuel ovens, and in industrial uses like making nitrogen fertilizer. It is also being explored as an <a href="http://www.nytimes.com/2010/01/14/business/energy-environment/14boone.html " target="_hplink">alternative fuel</a> for automobiles.

  • Con: Prices Are Volatile

    Natural gas has been caught in a <a href="http://www.nytimes.com/info/natural-gas/" target="_hplink">cycle of boom and bust</a>, as investors have grown excited about new drilling technology that made deeper reserves available, flooded the market with gas, and caused a collapse in prices. With the added volatility of oil, which affects the attractiveness of natural gas as an alternative, it’s hard to ever know for sure whether it is a good investment.

  • Pro: The Infrastructure Is Already In Place

    Unlike wind power, charging stations for electric cars, and smart grids, the infrastructure for distributing natural gas is <a href="http://www.boston.com/business/technology/articles/2010/11/08/process_removes_carbon_yielding_cleaner_natural_gas/" target="_hplink">already in place</a>. A network of pipelines <a href="http://www.ucsusa.org/clean_energy/technology_and_impacts/energy_technologies/how-natural-gas-works.html#naturalgasprocessing" target="_hplink">extends </a>across the US and continues to expand.