The woman, who has not been named, was tossed into the water as her home collapsed in the Channel-Port Aux Basques area of Newfoundland on Saturday, according to the Royal Canadian Mounted Police (RCMP) in Newfoundland and Labrador.
A spokesperson for the RCMP said that the woman was pulled to safety and taken to hospital.
The extent of her injuries is unknown at this time.
Police said that they had also received a report of another woman being swept out to sea but that they were yet to confirm the account as the conditions remained too dangerous for search crews to respond.
Between eight and 12 homes on the edge of the extreme southwestern tip of Newfoundland are believed to have been washed out to sea since Fiona barrelled into the area on Saturday.
Chilling images showed entire structures swept out to sea and submerged deep in water, while others had their roofs ripped off, with one local resident describing the scenes as “utter destruction”.
“I’m seeing homes in the ocean. I’m seeing rubble floating all over the place. It’s complete and utter destruction. There’s an apartment that is gone, that is literally just rubble,” said René J Roy, a resident of Channel-Port Aux Basques and chief editor at Wreckhouse Press. “It’s quite terrifying.”
Mayor Brian Button said in a video message posted on Facebook that people in dangerous areas had been evacuated to higher ground as he urged anyone who was told to leave to follow the official instructions.
The mayor warned everyone else to continue to stay home and not to be tempted to leave their homes to photograph the extreme weather event.
“We’re still in this storm,” he said. “This is serious, I’m serious with you when I am telling you need to stay put.”
He added: “Stay away. This is a state of emergency that we are in.”
The mayor vowed that the community would “get through this together” and urged anyone who has been displaced to contact the Canadian Red Cross.
Fiona made landfall in Canada early on Saturday, slamming into Nova Scotia and lashing the region with strong rains and winds of up to 92mph (148 km/h).
Homes in its path were pummelled and power lines downed, leaving more than 415,000 residences in Nova Scotia – around 80 per cent of people in the province – without power that morning, according to the region’s power outage centre.
In the hard-hit province of Prince Edward Island, over 82,000 customers were affected, along with around 44,000 in New Brunswick.
Power outages in hard-hit areas could last for several days, officials have warned, as conditions remain too dangerous for crews to begin repairs.
Peter Gregg, CEO of Nova Scotia Power, said in a press conference on Saturday that more than 900 power technicians were headed to Nova Scotia, where Fiona first made landfall early on Saturday morning.
But, because the province is still enduring an active storm, workers will have to wait to start assessing the damage and restoring power.
“We’re working to restore power as quickly as we can, as soon as it’s safe to do so,” he said.
Canadian Prime Minister Justin Trudeau held an incident response meeting with government officials on Saturday morning as he postponed his visit to Japan to deal with the crisis.
“I’m thinking of everyone affected by Hurricane Fiona – I want you to know that we’re here for you,” he tweeted on Saturday afternoon.
“I convened an Incident Response Group meeting with Minister @BillBlair and officials this morning. Our government stands ready to support the provinces with additional resources.”
Fiona transformed from a hurricane into a powerful post-tropical cyclone late on Friday, before striking the Canadian coast.
This came after it tore through the Caribbean earlier this week, killing at least eight people.
One of the victims was a four-month-old baby who died as its mother was unable to reach a hospital because of roads being blocked.
The hurricane ploughed into Puerto Rico, the Dominican Republic and Guadeloupe, where thousands were left without power.
Five days on, more than half of Puerto Rico is still without power.
Meanwhile, Florida is bracing for a separate hurricane this week as Tropical Storm Ian is forecast to build into a Category 3 hurricane before it reaches the Sunshine State on Wednesday.
The Associated Press contributed to this report