Water floods sections of Sackets Harbor on Monday after the lake reached its highest level since record keeping began in 1918. (Provided photo — Kathy Taber-Montgomery, Watertown Daily Times)

Lake Ontario water levels set a record Friday, and levels have climbed higher since then.

According to the International Lake Ontario-St. Lawrence River Board, which monitors water levels, the lake level reached 248.98 feet on Friday, breaking the existing record of 248.95 feet established in 2017.

The International Joint Commission, however, announced Monday that it has climbed to 249.02 feet since the record was broken, caused primarily by additional rain across the Great Lakes basin. The agency expects the lake level to “continue rising gradually” for several days until peaking in one to three weeks, according to a news release.

Water from the elevated lake, pushed by a stiff wind Monday, has flooded Brown Shores Road in Sackets Harbor, closing it to all but local traffic.

“There are private home structures there, for many people it’s year-round housing,” said Mayor Molly Reilly. “A section of the road is getting significant wave action and there’s nothing to mitigate the wave activity. There are also three culverts that cannot do their jobs because of the wave action.”

The closure comes after the National Weather Service announced potential for wave action to increase lakeshore flooding in Jefferson and Oswego counties between Sunday, June 2 and Tuesday, June 4.

Frequent rainfall across the Lake Ontario and the entire Great Lakes basin has been a key contributor to the high levels of Lake Ontario. Other crucial factors include outflows from Lake Erie, which also received record high rainfall, and reduced outflows from the Robert Moses-Robert H. Saunders Power Dam in Massena and Cornwall, Ontario, done to mitigate the flooding near Montreal in the lower St. Lawrence River and Lake St. Louis.

The river board, however, has since increased outflows from the dam when conditions have permitted. The height and outflows from the Ottawa River, which flows into the St. Lawrence River, have slowly declined, allowing the board to release more water from Lake Ontario through the dam.