• Kathleen Graham crawls beneath a curtain of stalactites inside Raspberry Rising cave

    Kathleen Graham crawls beneath a curtain of stalactites inside the Raspberry Rising cave system in B.C.’s Glacier National Park. (Photo: Christian Stenner)

It’s Hallowe’en night, and total darkness envelopes me as I crawl through a tunnel deep inside a mountain in British Columbia’s Glacier National Park. I am one of the first humans to lay eyes on these forbidding passages. At a fork, I choose to go right, and enter a room where I can stand. The beam of my headlamp lands on the skeleton of a rodent, its tiny bones surrounded by white calcite. A dead end. 

Methodically, I backtrack to the junction and take the left branch, moving carefully around delicate calcite columns and a glistening spiral stalactite. What I see next almost takes my breath away. A floor of spiky, pure white calcite crystals stretches from one side of the tunnel to the other and continues down the passage as far as my headlamp can illuminate. Further along, soda straws — thin, hollow tubes formed by calcite accumulating with each slow drip of water — dangle from the ceiling. One has crystals spreading from it like the branches of a pine tree. 

These remarkable structures formed from a specific and unique combination of processes over many thousands of years. Their discovery solidifies this cave’s significance as one of Canada’s natural wonders. Not only is it the most beautifully-decorated cave in the country, its unique biome is attracting interest from scientists in a range of disciplines, from climatology to medicine.

The “Crystal Tube,” a passageway inside Raspberry Rising lined with crystal spar formations and soda straw stalactites. (Photo: Christian Stenner)

The mystery of the cave

In the 1880s, when Major Albert Rogers surveyed what is today known as Rogers Pass, he noted the presence of a cave with a spring emanating from it, but it would be nearly a century before serious efforts were undertaken to explore it. In 1966, Dr. Derek Ford and a team of researchers from McMaster University visited the area and identified the potential for a vast cave system to be present between the spring and a whirlpool that swallows the meltwater of a glacier in a nearby valley.

In 1972, legendary caver Mike Boon made the first successful dive in the spring, by then called Raspberry Rising, and emerged in an air chamber on the other side of a flooded sump, only to find a powerful underground waterfall blocking further progress. The cave remained at only 80 metres of known length for another 30 years.

Then, in 2012, Nicholaus Vieira climbed the waterfall using modern equipment, and the vast cave system theorized by Dr. Ford was finally accessible. The following year, a Royal Canadian Geographical Society-funded expedition led by Vieira mapped a further 2.3 kilometres of Raspberry Rising, and most recently, a team of Canadian and American speleologists led by myself and Kathleen Graham has continued to explore deep into the mountain. As of 2019, we have surveyed a total of 5,504 metres of passages, confirming Raspberry Rising as the longest marble cave in Canada, and the second-longest cave found in a Canadian national park.

The challenges of exploration

Our team makes a strange sight on a cold winter morning at the Discovery Centre at Rogers Pass. While groups of backcountry skiers check in with Parks staff and don their gear for a day of touring, we’re sorting scuba tanks, dry suits, masks, regulators, lead weights, cave suits, ropes, harnesses, and carabiners, along with the avalanche transceivers, probes and Gore-Tex that are required for any winter pursuit in the Rockies.

Carrying all this gear partway up a mountain slope in winter is challenging enough, but we face other hurdles in getting to Raspberry Rising. The cave is closed to the public, and this unique and fragile karst system is protected under the Canada National Parks Act. Research and exploration is only conducted by experienced caving professionals under an approved Parks Canada Research and Collections Permit.

Another system of permits is necessary to travel in the region in winter. The cave is located in the most notorious avalanche corridor in Canada and the epicenter of Operation PALACI, Canada’s longest-running military mission. Since 1961, Parks Canada and the Canadian Armed Forces, under Operation PALACI, have partnered on the world’s largest mobile artillery avalanche control program in Glacier National Park. With 134 avalanche slopes able to affect this vital transportation corridor, 105mm howitzers are used to set off avalanches at controlled times to help keep the roads and rails open and safe in winter.

These are the same slopes we must traverse to get to the cave. It’s risky and complicated, but necessary, as winter is the only time one can attempt to enter the cave. At any other time of the year, the volume and force of the water rushing through it makes it impossibly dangerous. 

To get into the cave, we have to make a short but technical dive in very cold water, with visibility ranging from clear to something like chocolate milk. The deepest point in the dive is also the tightest: all team members and their equipment must pass through a 40-centimetre-tall slot underwater before surfacing in a spacious hall at the base of the waterfall. Then, it’s a 25-metre climb up through the spray. 

Kathleen Graham and Christian Stenner with the flag of the Royal Canadian Geographical Society inside Raspberry Rising cave

Kathleen Graham and Christian Stenner with the flag of The Royal Canadian Geographical Society inside Raspberry Rising. Photo: J. Habiak)

Whereas most caves in Canada are formed in limestone, here the rushing meltwater from the distant glacier carved through a narrow band of marble and created multiple levels of cave passages, like floors in a building. As such, the cave passages climb steadily upwards from the entrance, and unlike most cave explorations, the team has had to explore the system from the bottom up.

In addition to having to climb up and around many underground waterfalls, we have encountered four more flooded cave passages, most of which require scuba equipment to pass. The fifth sump — the furthest the team has made it into the mountain thus far — was a focus of recent exploration and one of the most challenging undertakings in a cave in Canada, or anywhere for that matter.

Cave diving requires thorough preparation and a calm mind. Attempts to reach the sump feeling warm, confident and focused were thwarted by mud slides, highway closures, missing gear, damaged equipment, and nerves. After three years of planning, moving equipment, and some false starts, it was finally “pushed” by the team in late 2018. A short distance in, the sump was found to be blocked by boulders underwater, with no spaces through which a human could fit. With this lead now exhausted, we will have to find another way to get further into the mountain. 

The most beautifully-decorated cave in Canada

In spite of the challenges of exploring Raspberry, each newly discovered passage has had the potential to reveal something amazing, which has motivated us to push on. The interaction of water and rock inside a cave creates formations that are dazzling in their variety — stalactites and stalagmites are just the two most famous examples of these speleothems.

Raspberry Rising contains hundreds of incredible formations. Calcite draperies flow like curtains from the ceiling down the walls of the cave. In the dry passages above the underground river, there are galleries containing hundreds of fragile soda straws, some up to two metres in length. Even the humble stalagmite can take wondrous forms. One in particular rises thickly from a ledge like a tree stump but is topped with a long, narrow horn extending upwards. I call it “The Narwhal.”

On one recent exploration, we found the largest cave pearls ever observed in Canada. Tucked away on a ledge, what started as single grains of material have morphed over time into a nest of pearls nearly the size of golf balls. If you were to break one in half, you would find it has rings like a tree, except that these layers were tens of thousands of years in the making.

Cave pearls inside Raspberry Rising

Cave pearls — some the size of golf balls — on a ledge inside Raspberry Rising. (Photo: Christian Stenner)

Another unique discovery in Raspberry Rising was a lone indigo stalactite hanging from the ceiling of an enormous room. Graham was the first to enter the 30-metre-high chamber and recalls the “absolute awe” that washed over her when she first saw the vivid blue stalactite. On the floor beneath it, a blue stalagmite had formed, surrounded by flowstone the colour of toothpaste. “I was so excited, I ran back to the other team members and said, ‘It’s blue! Blue like a Smurf!’” says Graham. Chemical analysis suggests the blue material is allophane, a hydrous aluminum silicate clay. We named the room — the largest discovered in the cave so far — “Blueberry Hall.”

Future potential

The story of Raspberry Rising is still being written. Some 60 unexplored “leads” have yet to see the light of a headlamp and still beckon the caving team. With its rich variety of speleothems, the cave could hold clues to past climate changes. Soil samples retrieved from the cave contain microbes that show promise as potential future antibiotics (see sidebar below). And recently, NASA researchers have shown interest in the Raspberry microbiome to further their studies in the growing field of astrobiology. The unique characteristics of the extremophile microorganisms found in the cave could hold clues to the evolution of life on Earth and guide our search for life on other planets.

In a world where it is easy to assume that everything has been discovered already, Raspberry Rising proves otherwise. The survey and study of this cave system and collaboration with other scientific disciplines is an example of how exploration and geography drive other forms of discovery. As Graham puts it, “Canada is so wild and raw; how many more treasures like Raspberry lie hidden just out of sight?” 

Related: RCGS-supported expedition discovers deepest cave in Canada