Yukon Electrical Co. Ltd. and Yukon Energy customers lost power once again this morning, this time because of an obstruction along the Whitehorse/Aishihik/Faro grid.

"We think that a tree has fallen on the line somewhere between Whitehorse and Faro - closer to Faro than Whitehorse," Yukon Energy spokeswoman Janet Patterson reported this morning.

"The guys can rule out a whole bunch of things - problems at the stations, and so on - so now they are driving out to check the lines for the obstruction."

By noon, workers had narrowed their search to the area between Carmacks and Faro.

"We are getting a helicopter to do a fly-over right away," Patterson said.

People from Whitehorse to Faro, including parts of Riverdale, Porter Creek, and north all the way to Faro, including Carmacks, Pelly Crossing and the Minto Mine, were in the dark beginning at 9:02 a.m.

All Whitehorse customers were back on the hydro grid by 9:20, 18 minutes after the power went out, Patterson said, while most other places were back on with diesel back-up power within the hour.

Approximately 4,000 Riverdale and Porter Creek customers lost power because "the distribution system did what it was supposed to do," Craig Steinbach, Yukon Electrical's manager of customer service, said today.

"When the transmission system goes outside of operating parameters - either with too much energy or not enough - the equipment shuts itself off."

Getting them back on was fairly simple, he said. Others weren't so lucky.

Yukon Energy customers in Braeburn, a community of 17 residences, were without power until just before noon, Patterson said, as was the Minto Mine.

Twenty-five Yukon Electrical customers at Deep Creek were also without power until 12 p.m.

"They tried to reenergize," Jay Massie, Yukon Electrical's superintendent of operations, said of the delay, "but it went back off pretty quick; we're not sure what they're battling."

A total of 4,129 homes and businesses lost power this morning.

"What we're dealing with here is an overhead system that is subject to all sorts of uncontrollable factors," Massie said

"There's no science to it; we're just trying to keep up with Mother Nature."