Watch as large waves cause 'significant flooding' on part of Toronto Island

Strong winds caused large waves that breached sandbagging efforts onpart of Toronto Island Thursday eveningcausing "significant flooding" in some areas, officials say.

In a tweet, city spokesperson Brad Ross said the flooding is affecting the island's north shore, where some homes are surrounded by water and others may have water in their crawl spaces or up to their doors.

Water levels are higher on the western side, 30 to 40 centimetres in some parts, Ross said. Pump and sandbagging work will take up to 72 hours, with the focus right now on residential areas, he said.Non-essential vehicles from the mainland won't be allowed on the island during that time.

City staff are on site taking stock of the damage and will be working to restore barriers and pump away water overnight, Coun. Joe Cressy said in a tweet.

Neither official was able to say how many homes were affected as of Thursday evening. More information should be available Friday, said Ross.

Earlier this month, the Toronto and Region Conservation Authority issued a "shoreline hazard warning," advising that water levels in Lake Ontario were approaching those seen in 2017 when floodwaters inundated the islands for months.

In the advisory on May 1st, the TRCA said levels had reached 75.5 metres roughly the same as was seen in April 2017.

At the height of the flooding in 2017, the TRCA said, Lake Ontario had reached 75.93 metres.

Water levels in Lake Ontario generally rise through to late May or into early June, Rehana Rajabali, a TRCAsenior manager of flood risk management told CBC News.