MONTREAL - About 80,000 Quebecers, including thousands of downtown Montreal commuters were forced into the dark Thursday afternoon at around 4 p.m. when power went off.

The outage was caused by a malfunction at a Hydro Quebec's substation and left many downtown traffic lights off.

The outages also extended to the Laurentians and the Richelieu regions of Quebec.

At its peak, about 50,000 Montreal homes and offices, including crowded downtown facilities as McGill University, were in the dark.

Hydro officials managed to return the electricity swiftly and at around 5 p.m only about 3,000 Montrealers were still without electricity.