A 16-year-old cyclist from Victoria, B.C., was killed Sunday in Snohomish County during a charity bike ride.

The teenager was riding in a large pack at about 9:20 a.m. when he tried to pass and fell into oncoming traffic, said Kristin Banfield, a spokeswoman for the city of Arlington, where the accident occurred.

The boy, whose name was not released, died at the scene, she said.

Police have ruled his death an accident.

Joined by his mother and uncle, the boy was one of about 2,640 cyclists participating in a two-day ride from Vancouver, B.C., to Redmond to raise money for cancer research. He was traveling south on Smokey Point Boulevard, near 204th Street Northeast, when he fell, Banfield said.

“He decided he was going to pass this group of riders and pulled out into a northbound traffic lane,” she said. “Somehow, he fell, and a vehicle struck him.”

The driver is an Arlington woman in her 50s. Police determined she was going below the 35-mph speed limit and was not responsible for the accident, Banfield said.

“He fell right in front of her, and she had no time to stop, unfortunately,” Banfield said. “It was just a terrible accident.”

The fifth-annual Ride to Conquer Cancer, organized by the BC Cancer Foundation, raised $10.4 million for cancer research.

The ride was halted while rescue crews tried to revive the boy, but later resumed and finished in Redmond.

“This event is one of hope and optimism and people wanting to do a great thing to support cancer research,” Doug Nelson, president and CEO of the BC Cancer Foundation, said in a phone interview Sunday.

“When something like this happens, we’re devastated.”

He said the foundation will work with local officials and riders to evaluate route safety, as they have in previous years.

“We have hundreds of cancer survivors who participate,” he said. “A ride like this is really important to them. It gives people time to reflect on why they’re riding and why cancer research is so important.”

Amy Martinez: 206-464-2923 or amartinez@seattletimes.com. On Twitter: @amyemartinez