Emergency personnel are "scaling back" their search for a Toronto-area student who is presumed drowned after she was swept over Niagara Falls on Sunday night.

The 19-year-old woman, an international student from Japan, was with a friend when she fell into the Niagara River after climbing over a railing to pose for a picture at Table Rock on the Canadian side of the falls.

The woman was sitting on a block pillar with her legs straddling the railing when she stood up, possibly to climb back over the railing, and apparently lost her footing, Niagara Parks Police said.

She fell into the fast-flowing river about 20 metres upstream from the falls and was carried over the edge by the river's swift current at about 8:30 p.m.

Her name hasn't been released. Police said investigators are working with the Japanese consulate to notify the woman's next of kin. As of 6:30 p.m. they still had not been successful.

Police described the incident as "death by misadventure," saying foul play isn't suspected.

"We have about 11 million people a year that attend here and most leave here safely, but if you are a young adult and you choose to climb over a restraining barrier there is unfortunately consequences and this time they were tragic," Niagara Parks Police Chief Doug Kane told CP24.

The woman's fall was recorded by security cameras.

Emergency personnel immediately began scouring the water, using lights and a thermal imaging camera, but they were unable to locate the woman before the search was called off for the night. The search resumed Monday morning as search parties combed the water and the shoreline for the woman. A helicopter from the Eric County (N.Y.) Sheriff's Department assisted in the search, but has since been sent home.

Due to elements, only the Maid of The Mist is equipped to search near the base of falls.

The local fire department is no longer involved in search and police say recovery of the body could take "weeks."

"Sometimes there is no recovery," Insp. Paul Forcier told CP24.

This is the second search and rescue operation that emergency personnel have conducted at Niagara Falls in as many days.

Early Sunday morning, firefighters rescued a 27-year-old man who fell about 10 metres down the side of the Niagara Gorge.

Police said the London, Ont., man escaped with non-life-threatening injuries. The man is facing charges under Ontario's Niagara Parks Act.

With a report from CP24's George Lagogianes