High winds moving through southern Ontario have downed power lines and trees, causing power outages on both sides of the Ottawa River.

High winds tree downed car Bedford Crescent

High winds snapped this tree on Bedford Crescent in Manor Park on Friday. (Sarah and Michael McCabe)

Hydro Quebec said about 21,000 of its customers were without power as of 5 p.m., up from about 12,000 earlier in the day.

In Ottawa, about 900 Hydro Ottawa customers were without power as of 5 p.m., mainly in the west end of the city.

And in Hydro One territory, thousands of customers were without power across southern Ontario.

Environment Canada said an intensifying low-pressure system is tracking through northern Quebec this afternoon, causing strong and gusty winds in southern Ontario.

"Wind gusts between 70 km/h and 100 km/h are likely for most areas until early this evening," according to a special weather statement posted on the weather agency's website.

"Winds have begun to weaken over south central Ontario early this afternoon and will weaken late this afternoon over eastern Ontario."

Corrections

  • An earlier version of this story said Hydro Quebec reported that nearly 205,000 of its customers were without power on Friday afternoon. In fact, about 12,000 customers were without power.
    Nov 01, 2013 4:28 PM ET