A 17-year-old girl has died in a skiing accident at Blue Mountain resort northwest of Toronto, the OPP says.

Const. Theresa Van Boven of the OPP's Callingwood detachment  told CTV Newsnet on Thursday that the girl had been wearing a helmet when she struck a tree.

Emergency workers transported the girl to Collingwood General and Marine Hospital where she was later pronounced dead.

"Details will be revealed later. There will be a post-mortem tomorrow," she said.

"It's a very tragic event. It was a clear, good day to ski," Van Boven said.

The victim has been identified as Elisabeth Reurink, who had been a Grade 12 student at Catholic Central High School in London. She was at the resort on a school trip.

Reurink had been skiing with a teacher. The accident was reported to the OPP at about 10:50 a.m.

Her identity wasn't officially released, but word spread quickly through social media channels on the Internet. In a statement, the school board called Reurink "a lovely young woman who was very involved with athletics, an excellent scholar and very devoted to her family."

Classmates returning to London, who weren't aware she had died, were met by grief counsellors.

The Blue Mountain website said it had 35 of 36 runs open on Thursday. A spokesperson for the resort, located 137 kilometres northwest of Toronto, asked ctvtoronto.ca to refer to an online OPP report for information.

Two other serious accidents have occurred at Blue Mountain this winter.

There have been other recent ski deaths at Ontario resorts.

Another ski death occurred about two weeks ago at Snow Valley resort near Barrie. "James" Boo Sung Moon, a Grade 8 South Korean visa student, lost control and struck a tree.

It was only the second time he had been skiing. In that instance, Boo Sung Moon hadn't been wearing a helmet.

On Sunday, a 45-year-old Toronto man died at Beaver Valley Ski Club, located about 30 kilometres southwest of Collingwood. John Zsolt had been wearing a helmet when he crashed and fell into a tree.

Premier Dalton McGuinty has brushed off calls to make helmet use mandatory during skiing.

With files from The Canadian Press