Ice on power lines
Extreme and fluctuating weather conditions, including high humidity, freezing temperatures, and ice storms can cause ice to form on power lines. Ice weight can put a lot of stress on power lines and damage equipment. Snow, rain, or freezing rain can also create conditions to start pole fires.
In windy conditions, icy lines can whip violently and gallop, causing tie wires to break, wood poles and cross arms to snap, and even steel towers to crumple.
If you see damaged poles or ice on power lines
- Call us at 204-480-5900 in Winnipeg or 1-888-624-9376 outside Winnipeg if you notice excessive ice build-up on a section of lines, leaning or snapped poles, or downed lines.
- Stay clear of low or sagging lines and remember that travelling under these lines can be dangerous.
- Treat any downed line as though it is energized and keep others away. Never attempt to move or repair lines or remove tree branches.
- If your vehicle accidentally makes contact with a downed line, do not get out of it. If it is safe to do so, back slowly away from the line or wait for help to arrive.
How we remove ice from power lines
Ice-covered power lines and high winds pulled and twisted this tower in 2012.
We remove ice from power lines as quickly as possible to prevent equipment breakage and loss of power. Whether we melt or roll ice depends on current temperatures, weather conditions, the amount of ice build-up, location, length and configuration of lines, and our ability to isolate selected lines.
Ice melting may require us to shut off power to certain customers, about 1 to 6 hours, to help prevent significant equipment damage resulting in longer outages.
A controlled short-circuit is placed at one end of a line. The current flow creates a temperature increase that heats up the line and melts the ice. 2 crews of 3 to 4 people each (one crew working outside on the equipment and the other crew working in a control room), we can melt the ice off 30 to 50 km of line in about 3 hours, often with no customer outages.
Ice rolling involves attaching a roller to the end of a long pole or rope which is then hung onto a conductor. In windy or wet weather, the power is turned off. In some weather conditions, it can be left on. We pull the roller along the power line, cracking the ice off as it goes. This is a manual procedure often done in freezing rain and storm conditions. Rolling is done when melting is not an option. A 10-person crew can de-ice roughly 1.6 km of line per hour.
Manitoba Hydro de-icing techniques
See how our crews use the ice rolling technique to remove ice from power lines.