“Wind chills near minus 50 to minus 60 continue” across territory

Environment Canada’s extreme cold warnings persist across much of the territory. Today, cold warnings were issued for Wekweeti, Whati, Behchoko, Sachs Harbour, the Fort Good Hope region, the Tulita and Norman Wells region, Ulukhaktok, Deline, the Inuvik region, Paulatuk, Tsiigehtchic, Fort MacPherson, the Aklavik region, Colville Lake and Tuktoyaktuk’s East Channel region, with wind chills of up to minus 60 degrees expected.

Wind chills of up to -60 are expected in the Aklavik region until Thursday morning, while in Colville Lake and Tuktoyaktuk, the extreme cold is anticipated to extend for longer periods.

According to Environment Canada’s report, the temperature will moderate to some degree during the daytime for “some communities” but will likely drop again overnight.

The federal agency reported that Colville Lake and the Tuktoyaktuk East Channel region are under  orange level warnings. The agency forecasted that the temperatures “will moderate somewhat this afternoon, but are anticipated to continue.”

Forecasters reported that for Tuktoyaktuk, the extreme cold “with wind chill values between minus 50 and minus 60” will likely continue past the weekend.

“Temperatures will remain in the mid to low minus 30s with wind chill values near minus 50 at times through the next week. Any associated impacts may not see opportunities for improvement until the following weekend.”

In Tuktoyaktuk, forecasters say the coldest of the wind chills are expected today and “will improve slightly tonight as winds weaken.”

Northwest Territories Power Corporation has posted advisories on social media regarding potential outages in the region.

“NTPC is monitoring the situation to ensure we are prepared for these challenging weather conditions. If outages occur, crews will be dispatched as soon as it is possible to safely do so.”

Last week, a full community outage took place in Tuktoyaktuk amid wind chill temperatures in the minus 50 zone. The outage began in the early morning hours at about 2:30 am with power being restored by about 9:00 am.

Doug Prendergast with NTPC said the outage was due to the “failure” of a breaker at one of three generators at the local plant which is now being replaced.

“There are three generators in the Tuktoyaktuk plant, which is the case for most of our thermal communities. Two of the generators have sufficient capacity to meet peak demand in the community so if one of those units is unavailable, there is still sufficient generation available. The third generator has a smaller capacity and is used primarily in the summer months to improve engine efficiency when electricity demand is lower. This arrangement of generators in the local plant ensures there is backup generation available if one of the large unit needs to go out of service for oil changes or other maintenance,” said Prendergast.

Prendergast reported that while an outage would typically automatically cue another generator online this did not happen in Tuktoyaktuk because of the way the breaker is set up to work in the system.

“However, the breaker for the online unit remained closed due to the failure and would have caused the other generators to short out if their breakers were closed. Power could not be restored until that generator could be manually tripped.”

“Under most circumstances, another generator would automatically come online. In this case, a generator fired up but, as soon as the breaker closed, it would trip due to the failed breaker on the original unit remaining closed and being offline,” added Prendergast.

Prendergast reported that because the trip coil that caused the breaker failure is “small” NTPC currently does not have a preventive maintenance for that issue other than a resistance test.

“Breaker and relay testing was completed this past summer in Tuktoyaktuk and there were no signs of imminent equipment failure,” he said.

The repair called for a trades crew to travel from Inuvik along with equipment to make the needed repairs.

Story Update: 
At about 9:30 pm MT, Environment Canada downgraded the orange level warning to a yellow level for Colville Lake, but warned that wind chill values near minus 50 are expected to continue.

“Conditions will moderate by Thursday morning but cold air will move back into the area starting Saturday afternoon.”