A group of BASE jumpers used parachutes to glide safely to the ground after leaping off a highrise building under construction in downtown Vancouver, but now the danger for them could be the long arm of the law.

Yaletown resident Mike Daniels was in his 36th-floor apartment between 1 and 2 a.m. Monday, Sept. 4, when his wife told him someone had jumped off the building across the street.

As he ran out to his balcony, Daniels saw one jumper with his parachute already open floating by the building.

"And then the second guy, as I ran out, jumped from either the rooftop or one of the top two floors where there's no windows. And I watched him just kind of sail down this way, and he curved around and landed just down there,” said Daniels, pointing to the middle of Pacific Boulevard next to David Lam Park, several hundred metres below.

The thrill seekers had jumped from the top of The Charleson, a 43-storey residential building under construction at the corner of Pacific and Richards streets. As the jumpers landed, several people called 911 to report what they had witnessed.

Vancouver police sent officers flooding into the area but they could not locate the BASE jumpers.

"It's not safe. It ties up police resources. And you could get seriously hurt,” said VPD Sgt. Jason Robillard.

In June 2016, American Gary Kremer died when his chute failed to open properly during a jump from the Stawamus Chief in Squamish.

The year before that, in March 2015, Vancouver-born Bryan Turner lost his life in a BASE jumping accident at Snake River Canyon in Twin Falls, Idaho.

"There's all kinds of unknown variables. The wind could pick up. You could get seriously hurt. It's just unsafe on a lot of levels and we want to discourage this type of behavior,” Robillard said of BASE jumping in urban areas like Vancouver.

If the jumpers are caught, they could be charged with trespassing and mischief.