At least five boats full of high school students capsized in high winds along the waterfront in Hamilton early Thursday, but police have now accounted for those who were tossed into the water.

About 90 rowers, from a handful of different Hamilton-area schools, were on the water at 7 a.m. when the wind suddenly brought gusts of up to 90 km/h.

The students went on the water shortly after 5 a.m., when conditions were calm.

George Gage, president of the Leander Boat club, described it as a "freak storm" that turned the water from calm to churning in a matter of minutes.

"The bay was flat calm at 5 a.m.," said Gage. "The weather alerts that we saw were for midday, nothing that would warn us it would come up this quickly."

Three marine units from Hamilton and Halton Region police recovered the students. Some of the students were carried by the frigid waves well away from where their boats had capsized. 

Two rowing boats were lost and a handful of coaching boats sank after taking on water. A total of 30 students ended up in the water. Nine were taken to McMaster Hospital and treated for mild hypothermia.

Police said everyone has now been accounted for, although they couldn't say exactly how many people ended up in the water.

Environment Canada had issued wind warnings for Hamilton, Toronto and a large chunk of the Golden Horseshoe earlier Thursday.

The Burlington Skyway Bridge was closed Thursday morning because of the winds.