Here's why a massive cave in a B.C. park went undetected for so long

VANCOUVER -- Researchers who discovered what might be the largest cave in Canada believe it may have gone undetected for such a long time because it was concealed by snow and ice that only recently melted due to climate change.

The cave, located in a remote section of B.C.'s Wells Gray Provincial Park, was spotted by a crew of wildlife biologists in a helicopter who were conducting a population survey of mountain caribou in 2018. The cave's entrance pit is estimated to be about 100 metres by 60 metres, and it ends in a spring located just over two kilometres away, about 500 metres lower than the entrance.

Researchers believe a "perennial snowfield" might have helped conceal the entrance to the cave until recently, when the snow plug collapsed at some point in the last decade, according to a paper recently published in the Canadian Journal of Earth Sciences.

"Basically, it wasn't seen because it has always been filled with snow," said researcher Catherine Hickson, a member of the team investigating the cave who visited the site in September 2018. "From a geological or natural spectacle perspective, the warming climate has revealed this cave."

According to the research paper, the collapse of the snow plug is "likely related to climate change as evidenced by the gradual recession of glaciers in the immediate area." The researchers say this is why the cave is not included in any list of the park's features since it was founded in 1939.

Hickson said even the area around the cave was under a glacier until the late 1800s. As the glacier receded from that area, an ice plug, which she compares to a sink stopper, was in place for the next few decades and has likely only melted out recently.

"The shaft was likely not visible and the feature appeared as a large snow-filled depression with a stream disappearing under the perennial snowfield," the paper said. "It was found due to the gradual dissipation of the perennial snowpack as seen in many other western Canadian karst areas."

Hickson said there is a spring down the slope from the cave entrance which would have started to emerge from under the ice closer to the end of the last ice age thousands of years ago.

"So people would've seen that spring, and if they were geologists they would've said, 'oh, I wonder where that water is coming from,'" she said. "But nobody would have had any inkling the size, the magnitude of this cave."

Hickson said the cave is at least two kilometres long and more than 150 metres deep. To put that into context, Hickson said the Statue of Liberty, including its base, would "completely disappear" inside of it. At the time of its discovery, Hickson told CTV National News the cave was "unprecedented" in terms of its size and said she had never seen anything like it.

The Canim Lake Band (People of the Broken Rock, The Tsq'escenemc) may have some traditional knowledge of the cave, and researchers plan to speak to them to get more information, according to the paper.

When it was first discovered, those who spotted it from the helicopter nicknamed it Sarlacc's Pit because it bears a similar resemblance to the lair of Sarlacc, a creature from "Star Wars: Return of the Jedi." However, the cave has not been officially named yet and will only receive one after consultation with First Nations groups, Hickson said.

The researchers have applied for a multi-year research permit with BC Parks, and if granted, would launch an expedition to explore the cave in fall 2021. This would include cave mapping, geological mapping, dye tracing, and the exploration of other nearby karst features. Hickson said the expedition needs to take place in September as it would be one of the driest times of the year.

Even though the cave is in a remote part of the park that is difficult to access, its exact location is being kept under wraps in order to preserve the area. BC Parks has also threatened fines of up to $1 million a day or as much as a year in prison for those who venture near the newly-discovered cave or its surrounding area.

Officials warn the risks of venturing near caves include falls, loose rocks, and fast-moving water, which could lead to hypothermia, drowning, serious injury, becoming lost or getting trapped from rising water. It would also put rescuers at risk as cave rescues are "highly technical and resource-intensive."

"It takes hours of work and dozens of volunteers to move an injured person a few hundred metres in a cave," a statement on the BC Parks website said. "Deploying to a remote location such as this cave and sustaining rescue volunteers for the duration of the rescue operation is by itself a significant challenge."