Yukon Energy is warning people about the dangers of boating through control gates after a near drowning this week.

The near tragedy happened Monday at the Lewes River Control Structure, about 40 kilometres south of Whitehorse. 

A canoeing party of six in three canoes tried to go through the gates.

They did so despite the prominent warning signs and a boat lock designed to help boaters get around the structure, said Yukon Energy spokesperson Janet Patterson.

Two of the canoes passed through a gate, but the third one capsized. A female passenger was trapped under water.

Yukon Energy staff, who were working on the structure, were not able to reach the canoe in time to help.

"It was incredibly scary,” Patterson said. "She was under for a number of minutes.”

Eventually, the woman was able to break free of the strong current and one of the other canoes came back to pull her out.

Patterson said it appears the group set off from the boat launch upstream wearing life jackets, but by the time they reached the gate some had removed their safety gear.

The second person in the capsized canoe was able to grab his life jacket and put it on before the current dragged him downstream, where he was rescued by his travelling companions, she said.

This is not the first time staff have seen boaters choosing the more dangerous route.

"I don't know why,” Patterson said. "It is incredibly dangerous, and there is a boat lock. People don't have to take that risk.”

Staff were unable to reach the boaters before the group moved on. Patterson said it appears the group was all right.

The more than 30 gates, which are designed to help control the flow of water to the dam from Marsh Lake, are all open over the summer, Patterson said.

Yukon Energy is planning a public information session at the control structure this summer to help people understand the dangers of the gates, and teach them how to use the boat lock.