DEVELOPING: The U.S. Coast Guard and Canadian authorities are scouring Lake Erie for four fishermen whose 19-foot boat sailed from a Michigan park a day earlier.

The men, who are between 50 and 70 years old, left Sterling Park in Monroe, Mich., Thursday morning and had planned to return by 4 p.m., Greg Fondran, a search and rescue controller at the U.S. Coast Guard's District Nine Command Center, told FOXNews.com.

Fondran said three of the four men have cell phones with them but have not answered calls by authorities. The last incoming and outgoing calls received and placed by the phones were at about noon Thursday, he said.

Weather conditions have not been severe, Fondran said, leading authorities to believe the 19-foot boat likely had not capsized or overturned.

"Though it's always possible," he continued. "You can get a rogue wave and all of a sudden, you're taken over."

Family members contacted the Coast Guard at about 9 p.m. Thursday. Boats, helicopters and other aircraft from the U.S. and Canada have been searching since that time, Fondran said.

"We're obviously concerned," he said. "We're considering it a distress case."