Averting a Power Outage

 Thanks to two observant Yukon Energy staff, we were able to address a problem with what's known as frazil ice before it resulted in a week-end power outage. 

Frazil ice forms on equipment such as the intakes to hydro units during times when it is below freezing yet before a stable ice cover has formed for the winter. It's been compared to rime icing, except frazil ice is always underwater. It forms very quickly, is often difficult to detect, and can cause major problems for operations involving water. For instance in 1914 the entire water supply for the city of St. Petersburg, Russia was cut off because of frazil ice.

This past week-end frazil ice started building up around the intakes to three of our Whitehorse hydro units. When our staff discovered the problem, the ice had formed to the point where it was preventing water from entering the hydro units.

Underwater divers were immediately called in and Yukon Energy employees worked with them throughout the week-end to melt the ice using very hot steam. The units are now back online and the frazil ice is gone.

Photo caption: Sean Grant from Canpac Divers surfaces after a final inspection of the intakes for three of the Whitehorse hydro units.