What it Means to “Set the Ice”

Throughout this long weekend, we will be spilling some water at our Whitehorse hydro dam.

We'll be doing what is called "setting the ice". By spilling water through the gates at our dam instead of letting it flow into our power canal, it allows a good cover of ice to form in the canal. Once the ice has set, chances are greatly reduced of "frazil" or slushy ice forming that can cling to our equipment and cause our hydro generators to shut down. You might remember that happened last year at our Aishihik facility and has happened in the past at our Whitehorse plant.

While we are waiting for the ice to form, we will shut down three of our four Whitehorse hydro units during the overnight period, and will only run two of the four turbines in the daytime. We will need to supplement with thermal (mostly LNG with a small amount of diesel) during this time.

We hope that the ice will set by the end of the weekend, at which time we can resume normal operations. 

Photo: If we do have problems with frazil ice on our equipment, divers need to be called in to use steamers to melt the sticky ice. By working to set this ice this weekend, we hope to avoid frazil problems.