In 2023, the documentary Subterranean followed two teams of cavers attempting to break major exploration records in Canada. One team was working to connect two cave systems on Vancouver Island to create what could become the longest known cave in the country. The other was exploring Bisaro Anima, near Fernie, B.C., in an effort to push the limits of Canada’s deepest cave. The latter expedition was led by Golden resident Katie Graham.
Bisaro Anima became Canada’s deepest known cave in 2018, when Graham and her team reached a depth of 670 metres. During an earlier expedition in 2017, the team discovered a flooded passage near the bottom of the cave, known to cavers as a sump. To explore beyond it, Graham would eventually need to scuba dive through the underwater passage.
Throughout the film, the team faces numerous challenges as it works to explore and map more of the cave. One major setback comes when Graham breaks her ankle approximately 400 metres underground during a 2019 expedition, forcing her to abandon her planned dive. Despite the setback, the team continues its exploration, and by the end of the film, the cave had reached a surveyed depth of approximately 682 metres.
This fall, Graham led another expedition into Bisaro Anima, pushing the cave’s known depth another eight metres and mapping an additional 1.1 kilometres of passages. The 24-person team entered the cave in late September and spent two weeks underground, with the expedition continuing into early October.
“Most of the crew had never seen the sump before. Their faces lit up with the beauty and intimidation of the teal blue lake,” Graham shared in a statement about the expedition.
“The task is daunting but exhilarating. Unravelling the mystery of what is around the corner? Why is the rock like that? It is a combination of time travel, a geology field trip, climbing a mountain peak, and camping in the rain- all so we can dive to know the secrets the mountain is hiding,” Graham continued.
Preliminary results from the expedition put Bisaro Anima at 690 metres deep and approximately 10.5 kilometres long. Along with extending the cave’s known depth, the team mapped 1.1 kilometres of additional passages and connected another cave entrance.
The project received support from the Royal Canadian Geographical Society and the National Speleological Society, alongside personal contributions from Graham and her teammates.
Graham is a longtime Golden resident and currently works as the chief financial officer of Edison Motors in Donald. She has continued to pursue cave exploration while based in the community.
Caving is a unique form of exploration because there is no way to know exactly what lies around the next corner without going there. Unlike much of the landscape above ground, where features can often be observed and mapped remotely, unexplored cave passages must be physically reached, surveyed and documented. In a cave system as extensive as Bisaro Anima, this can mean spending days underground navigating narrow passages, hauling equipment and carefully recording newly discovered terrain.
Setting records at this scale takes more than physical endurance. It requires patience, technical skill and a willingness to keep exploring when the outcome is uncertain.
