The remnants of former Hurricane Matthew have wreaked havoc along Canada's East Coast, washing out roadways, flooding neighbourhoods and knocking out power for thousands of people.

Newfoundland and Labrador has faced the brunt of the storm, with many communities declaring states of emergency due to heavy rainfall. A portion of the Trans-Canada Highway has been washed out in Terra Nova National Park, N.L.

Parks Canada says the road will be until later Tuesday, while road crews work to repair it. Officials say some N.L. communities could be cut off for more than a week.

鈥淚t really came with no notice. We just thought we were getting some heavy rain and then 220 millimetres later we found ourselves under water and under siege,鈥� Cape Breton Regional Municipality Mayor Cecil Clarke told CTV Atlantic. He says damage estimates are already in the tens of millions of dollars.

Clarke says Cape Breton鈥檚 drinking water is safe, but warns residents to avoid the vast pools of standing water as much as possible because of oil and sewage contamination.

鈥淲e were up past our waist in water trying to help a family trying to get the water out of their basement,鈥� said volunteer firefighter Robert Clamp.

All schools in the Cape Breton-Victoria Regional School Board were closed, and comfort centres were opened near Sydney, N.S. Several bridges and roadways have also been damaged or destroyed in N.L., as documented by many sharing images on social media.

There was also heavy flooding in parts of Cape Breton, N.S., where some roads were briefly turned into rivers. Video circulated of individuals standing on the road with water up to their thighs in some places.

By Tuesday afternoon, close to 230 millimetres of total rain fell in some parts of Sydney, N.S., according to CTV Atlantic鈥檚 weather anchor Alyse Hand.

Environment Canada says more than 100 millimetres of rain fell over mainland Nova Scotia by Monday evening.

Power is slowly being restored across much of Atlantic Canada. Nova Scotia Power (NSP) reported more than 144,000 outages across the province Monday, but that number dropped to about 33,000 by Tuesday evening. NSP says it could take until mid-morning Thursday to fully restore power to the region.

The storm knocked out power to 7,800 customers in Prince Edward Island, but that number has since dropped to 490, according to Maritime Electric. In New Brunswick, 171 customers remain without power, but could see it restored by late Tuesday evening.

Winds were the primary concern for the Maritimes on Tuesday, with some areas of Nova Scotia鈥檚 northern and southern coasts dealing with 100 km/hr gusts according to Sheerr. He said the gusts are expected to die down later in the evening however.

With files from The Canadian Press and CTV Atlantic