Masses of ice form in the lower Niagara River and around the American Falls as seen from Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

A man photographs ice masses formed around the American Falls as seen from Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

Niagara Falls State Park visitors look over masses of ice formed around the American Falls, photographed from across the Niagara River in Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

Pieces of ice flow over the Canadian “Horseshoe” Falls in Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

Masses of ice form around the Canadian “Horseshoe” Falls as seen from Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

A man photographs ice masses formed around the American Falls as seen from Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

A man photographs ice masses formed around the American Falls as seen from Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

Pieces of ice flow over the Canadian “Horseshoe” Falls in Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

Visitors Rosalie Vissers, left, and Rachel Houter take a photo near masses of ice formed around the Canadian “Horseshoe” Falls in Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

Masses of ice form in the lower Niagara River and around the American Falls as seen from Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

Visitors look over masses of ice formed around the Canadian “Horseshoe” Falls in Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

The sun rises over masses of ice formed around the Canadian “Horseshoe” Falls in Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

Masses of ice form in the lower Niagara River and around the American Falls as seen from Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)