'Extremely rare' ice blockage at hydro dam causes power outage in several Yukon communities

An underwater camera has confirmed that an ice blockage at the intake of the Aishihik hydro facility caused the power outage south of Whitehorse Tuesday morning.

Generating problem at Aishihik hydro plant leads to outages in Dawson City, communities south of Whitehorse

The Aishihik hydro facility is located 110 kilometres northwest of Whitehorse. (Yukon Energy)

An underwater camera has confirmed that an ice blockage at the intake of the Aishihik hydro facility caused the power outage south of Whitehorse Tuesday morning.

The camera found six to eight inches of slushy ice - the technical term is frazil ice - covering what's called the trash rack, said Yukon Energy spokesperson Janet Patterson.

She said Yukon Energy will dispatch a crew along with the City of Whitehorse steam truck to the Aishihik plant on Wednesday. They anticipate it will take about a day to remove the ice. 

Patterson said an ice blockage at the dam is an "extremely rare event" that has not happened in 25 years.

The blockage prevented water from getting to the generators, reducing output.

The power outage lasted an hour before power was re-routed to the affected areas. The outage affected Dawson City as well as communities south of Whitehorse to Teslin.

The Aishihik hydro plant is still offline and customers' power is coming from hydro facilities in Whitehorse and Mayo, along with diesel and LNG generation.

with files from Philippe Morin


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