New Technology Helps Rescuers Free Caver Trapped in Canmore Cave

A caver was rescued from Canmore’s Rat’s Nest Cave on Aug. 15 with the help of a new digital messaging system capable of transmitting through solid rock.

Communication is one of the biggest challenges during cave rescues, where conventional radios and cellphones do not work. The new system, used in a real rescue for the first time, allowed teams inside and outside the cave to communicate more quickly, saving critical time and helping rescuers coordinate people and resources.

Rat’s Nest Cave is located beneath Grotto Mountain, and is one of Canada’s longest known caves. The cave extends for several kilometres underground and includes narrow passages, vertical sections and large chambers. Guided tours take visitors through portions of the cave, while more technical areas are explored by experienced cavers.

At around 11:30 a.m. on Aug. 15, a man became stuck in the “Psych Squeeze,” a tight vertical section of the cave that is not traversed by tourists. He became lodged upright several metres down the passage and was unable to free himself. Cave guides also tried unsuccessfully to assist him.

The Alberta/BC Cave Rescue Service was deployed alongside paramedics from Canmore Fire-Rescue.

Rescuers used hammer drills to remove rock projections before placing bolts and rigging a progress-capture system, essentially a one-way mechanism that allows rescuers to pull someone upward without losing ground when they stop or rest.

Progress was painstaking, measured in “inches per hour,” according to a statement from Search and Rescue Alberta. Throughout the operation, rescuers also had to manage the risks of compression injuries, exhaustion and hypothermia.

The man was freed at around 10 p.m. and was able to make his way out of the cave with the assistance of ropes, but largely under his own power, shortly before midnight.

The rescue was declared complete by 2 a.m. after the man was assisted back to the trailhead. He did not require further medical treatment.

In total, 13 cave rescuers, 10 firefighters and two Kananaskis Mountain Rescue members took part in the operation, with another 13 cave rescuers on standby as a second wave. Five agencies were involved.

Communication during cave rescues presents a unique challenge because normal radios and cellphones cannot penetrate rock. Messages often have to be relayed in person, sometimes requiring rescuers to crawl or hike significant distances simply to pass along information.

“It’s just such a huge difference to have the ability to call somebody and talk, or talk via messaging system, where you’d otherwise have to literally walk, crawl, hike some distance to basically tell them the same information,” said Christian Stenner, provincial coordinator with the Alberta/BC Cave Rescue Service.

For the first time in a real emergency, rescuers deployed a new text-based, low-frequency digital radio system designed specifically for caves.

The system, which uses a specially adapted QDX-M radio, has been under development since 2023 by volunteer cavers with backgrounds in electrical engineering and amateur radio. The team has yet to determine its maximum transmission range, but has successfully communicated through at least 500 metres of solid rock.

The system uses an Android-based app running on a tablet connected to external hardware and a roughly one-square-metre antenna. Alberta/BC Cave Rescue now has eight units, replacing an older analog system that could produce partial or distorted audio transmissions.

“The units that we had, we only had a couple of them, they were somewhat unreliable and the transmissions could be garbled, or the antennas had to be just right. So there certainly were limitations. This is just a huge improvement,” Stenner said.

“To have a text message, then there’s no question as to what was being said, because you can read it, and it’s digital, which is all or nothing. You either get the message or you get zero. There’s no half message.”

Without the technology, Stenner estimates hours could have been added to the operation as information was slowly relayed from person to person. Instead, he was able to quickly learn when the man had been freed and more effectively coordinate the rescue from the cave entrance.

“Hearing that the subject had been freed from the squeeze and was able to move through the cave meant they weren’t injured and didn’t need a stretcher or a dozen people to help carry them,” Stenner said.

“That sort of thing was very, very good. It was a very positive thing to hear that. But it helped us to plan our resources and whether we needed to call additional people or send additional things in to help that person.”

Development of the new system was partially funded through grants from Search and Rescue Alberta and the Alberta government, along with significant contributions of money and time from volunteers.

Commercial low-frequency cave communication systems are available, but their cost is beyond what the volunteer-run organization can afford. The locally developed alternative is now attracting attention from other cave rescue organizations internationally.

“In partnership with the provincial government, Search and Rescue Alberta has, over the last few years, provided critical funding to the Alberta/BC Cave Rescue Society to support the development of a customized cave radio system which can penetrate solid rock,” Search and Rescue Alberta CEO John Alexander said in a release. “This was put into operational use for the first time this past weekend during a successful rescue.”

Alexander said the Aug. 15 rescue demonstrated both the importance of collaboration between emergency response agencies and the innovation of Alberta’s volunteer search and rescue community.

“The August 15 rescue of a subject in the Rat’s Nest Cave is a display of what can be achieved when multiple emergency response agencies come together in collaboration, and of the incredible innovation and initiative taken by our 1,500 volunteer search and rescue professionals who defy odds and overcome barriers every day, so others may live,” he said.

Alberta/BC Cave Rescue is Canada’s only dedicated cave rescue team and is part of the 33-team Search and Rescue Alberta network. It can only be deployed under the direction of a government agency, such as the RCMP.

Cave rescues are relatively rare. Stenner estimates the team has averaged about one rescue per year during his 20-year career.

Rather than commercializing the new communication system, the volunteers who developed it are working to share the technology with other rescue organizations.

“We’re definitely sharing all of that so that other groups can either build their own version or take essentially the plans of what we’ve done,” Stenner said.

The team plans to present the system to the European Cave Rescue Association this fall as part of those efforts.