The ice, weakened by the constant sunlight accumulated on the tops of the highest buildings in downtown Toronto, falls, and police are asking motorists and pedestrians to be vigilant.
The police and Toronto transit Agency Metrolinx suggests that the ice was falling in the areas around CN Tower, Union Station and the area of Bay Street for the financial district.
Bay Street was closed in both directions for several hours between the streets of Wellington and Harbour from the falling ice, but later was open.
Police are asking drivers to avoid those areas or go back if they see the falling pieces of ice, while pedestrians are urged to use exclusively underground transport and try not to go out.
Press Secretary Metrolinx Anne Marie Aikins said that some outdoor areas around Union station and the adjacent bus terminal are closed to pedestrians.