Winds of up to 80 kilometres an hour howled across Quebec overnight and have knocked power out for more than 100,000 customers.

Most of the outages are in Quebec City, Montreal, the Laurentians and the Eastern Townships. The number of interruptions have multiplied this morning as the strong winds persist.

Nearly 20,000 homes are without electricity in Montreal, and another 30,000 in Quebec City. All 4,570 customers on Île d'Orléans, near the provincial capital, are without power.

Hydro-Québec says it was prepared for the outages and is sending crews to all the worst-hit areas.

"Right now, we have over 200 crews that are out working in the various regions, through this wind as well," said Hydro-Québec spokesperson Lynn St-Laurent.

A fallen tree branch on a power line caused a small fire near a home in Quebec City. (Radio-Canada)

It says most outages were caused by fallen branches. In one case, a branch that fell on a power line caused a minor fire in a residential area in Quebec City.