Exploring the Depths of Sweden’s Longest Underwater Cave

In 1979, one of the participants in a Congregation of Swedish Federation of speleologists took a walk along the valley and paused briefly at a sandy beach by Dolancion. Being a lover of nature and diving, he gazed into the crystal clear water as he sipped on his coffee. That momentary staring led to the discovery of one of the longest caves in Sweden. And years later, his cave exploration group, the Expedition Buralvin, would be back for several dangerous expeditions in the deep waters of Sweden.

The Buralvin karst region is situated in the northern part of Sweden. It’s the longest underwater cave in the country and is explored and mapped by a team of cave divers every year. The river Beer Alvin flows from the mountains of Norway and enters the Swedish province of Yantlon. It meanders past the peaks and goes through the Buralvin valley where it disappears underground into what is known as The Buralvin Grotto. The great mass of water thunders as it is swallowed by The Grotto and reappears over one and a half kilometers away. The course of the water and the nature of the passage remain a mystery.

The Buralvin valley is well known for its numerous caves and is a popular destination for speleologists and cave enthusiasts. The existence of these caves is due to the calcareous limestone deposits that were formed around 450 million years ago. The river water seeps into every crevice, gradually dissolving the calcium over hundreds of thousands of years. As a result, the flow of water creates magnificent underground chambers in an ongoing process that continues to shape the landscape.

Dynamic processes also cause some areas to cave in, creating funnel-shaped depressions known as dolines. Back in 1979, the Swedish Federation of Speleologists gathered in the beautiful Valley of Buralvin to explore the area’s underground treasures. Bo Leander, a passionate cave explorer with extensive experience in discovering hidden gems, was among the participants. During a leisurely walk by Dolancion, the Dolan Lake, Bo and his companion stumbled upon a sandy beach while savoring a cup of coffee and admiring the clear water.

Beau noticed something intriguing at the bottom of the lake. He grabbed his dive gear and slowly descended to investigate the strange anomaly. Much to his amazement, he had discovered a small opening to a cave about four inches wide hidden beneath the gravel. Though too narrow to enter, it was an incredible find. Beau snapped photos of the opening with his Nikonos camera and marked its location on a map. Back then, no one could have predicted that Beau’s discovery would pique the interest of a diving expedition team over 30 years later.

Fast forward to present times, and the dedicated explorers known as the Bieralvin Cave Expedition team were equipped and excited to investigate the promising cave. After acquiring a permit to enter the reserve for a week, the team of select divers met to strategize and plan the mission that would become Expedition Bieralvin. Expedition Bieralvin is a remarkable project that has been running for 12 years. It comprises a team of great divers and support crew who brave the height of the Swedish winter to explore the Buralvin cave system in the Swedish mountains.

This project brings together a diverse range of experts, including divers, speleologists, local area experts, and surface staff. Around 20 to 25 people are involved in the project, each bringing their unique skills and knowledge to the team.

One dedicated member of Expedition Bieralvin is Mick Tilia, who has been part of the team since its inception in 2007. Mick is an experienced diver who began his diving journey in 1997 as an enthusiastic wreck diver. However, he discovered the fascinating world of caves and mines and has been exploring them ever since. Mick is also a media expert and photographer, working in a media agency and founding the Scandinavian Scuba Forum, “Daikarna.nu.” He is responsible for the team’s homepage and social media updates, producing movie clips for the expedition, as well as mapping new areas of the cave.

Another inspiring member of the team is Bo Leander, who discovered the entrance of the cave at the bottom of Lake Dolincion in July 1979. His passion for exploration and adventure continues to inspire the team. The team is made up of a diverse range of individuals, each with unique skills and experiences. Some of the other members of the team include Nicholas Muran, Stefan Barth, Marcus Nord, Per Sandberg, Dimitri Gorski, Mats Freudenlund, Lars Löfquist, Ola Löfquist, Magnus Ström Hall, Johann Udås, Oscar Svensson, and Stina Gabrielson.

Expedition Bieralvin aims to achieve three overall goals: conduct a comprehensive exploration, mapping, and documentation of caves situated in the Buralvin Valley; raise awareness and promote the caves within the region as well as the local community of Store Obulation; and collaborate with universities to advance scientific research through the provision of valuable data.

The First Attempt

In March 2007, Mick and a group of fellow expedition members were headed to Yomtland for a cave diving expedition. However, they received a call from the driver of the lead car in their convoy, who had encountered a mechanical issue and had to turn back. Additionally, a Class III warning was issued due to heavy snowfall, making the weather conditions dangerous. They decided to cancel the trip and return, ending the first expedition before it even began.

Expedition 2: The Biralvin Cave Diving Team

The following year, a group of 13 divers from the Biralvin Cave Diving Team came together for a second expedition. They focused on Dolan Lake, which had great exploration potential. One team explored Festen’s Grotto, while the other half explored Dolincion Lake. The team at Dolan Lake worked to clear away gravel obstructing the view of the opening that Beau had discovered years ago. They cautiously explored the cave and discovered a large space inside.

Encouraged by their findings, three divers geared up to enter the cave. They continued their excavation efforts and squeezed through a narrow opening, illuminating the unexplored world within. After evaluating the cave’s potential for further exploration, Dolan Lake became the central point for future expeditions. A 3D mapping technique was chosen to map the entire Biralvin cave system accurately.

Mapping and Safety Protocols

Navigation through cave systems relies on guidelines or lines that guide divers to the exit, even in low visibility. These lines are used to map the cave system, recording details such as directions, heights, depths, and turns. This manual process forms the foundation for developing a 3D model of the explored areas. Despite their achievements, the team recognized the need for enhanced safety and organization due to the challenges of cave diving in a remote mountainous and sub-arctic region.

Discovery of Rainy Hall and Cave Mapping

During an expedition, explorers discovered a vast chamber nearly half a kilometer inside the mountain. The chamber, named Green’s Hall, was filled with air and featured limestone formations in fantastic colors and shapes. To map the cave accurately, they used a transmitter and receiver developed by Beau, an expert in radio communication and homing. This allowed them to create precise charts by locating fixed points in space.

Explorations and Challenges

Over the years, explorations continued, resulting in the discovery of new sections and air-filled chambers. Each discovery posed unique challenges due to treacherous conditions, heavy equipment, and the risk of hypothermia. Safety protocols and risk analysis played a vital role in ensuring the team’s well-being. The explorers made incremental progress, mapping the caves and tracing the river’s flow.

Expedition Overview and Risk Analysis

Carrying heavy equipment and crossing treacherous, slippery slopes in rubble, while the diving itself did not present the greatest danger, the Airfield sections were fraught with risk. An injury such as a sprained ankle or a broken leg could have serious consequences since there was only one way out. Additionally, hypothermia was a significant concern as the water temperature was barely above freezing, and even a small leak in a diver’s suit or glove could quickly become life-threatening. As a result, a great deal of attention has been given to risk analysis and safety protocols in this expedition.

The Beeralvin Cave was further explored, resulting in an additional 360 feet being added to the known length, bringing the total to 7,306.55 feet. With this length, the cave was the sixth longest in the country, only 114 feet short of being the fifth longest. Satellite images revealed that the explorers had progressed about halfway to the Bureau of Grotto from one end, while 902 feet had been explored from the other end. With each passing year, the explorers make incremental progress toward their ultimate goal of tracing the river’s flow and mapping the connection between the two openings.

Following the Beeralvin 2018 expedition, the official length of the Dolins Yugraten Cave was determined to be 7,879 feet. However, no exploration diving took place in the cave in 2019.

2019 Expedition Details and Challenges

Instead, the team focused on mapping Coldhollet and discovering two new entrances in nearby Dolans. The expedition was carried out by 25 cave explorers, which included two new divers and two guests. Additionally, three locals from Stora Blasio and one guest from Yorm were present throughout the entire week. During the 2019 expedition, the team used a Lake Aviva GS-15 Rover attached to a six-foot carbon fiber pole and a Leica CS-10 field computer to measure points with their GNSS equipment. Bose tracking device was also used to locate the points. A total of 13 new points were measured using GNSS technology during this expedition.

The weather conditions during the expedition were initially stable, but they began to shift toward the end of the week. Heavy rain caused the water level in the caves to rise suddenly, resulting in the flooding of Dolan Lake and the base camp. As a result, a significant amount of equipment ended up submerged in water. The following morning, a rescue mission was launched to recover all of the equipment, which was ultimately successful. High-quality photographs were taken for documentation and media purposes. The pictures captured the beauty of Beeralvin and were taken by National Geographic photographer Irina Stangeshka and her team, who were part of the expedition.

During the same expedition, 53 dives were performed, which is fewer than the previous year. However, it’s important to note that only photo dives were done in the Dolans Yugraten, with the focus being on exploring the nearby caves. This caused a reduction in the total number of dives. The Dolans Yugraten has an established base camp, making it easy to dive, while diving in the other nearby caves requires a significant amount of preparation and logistics. Compared to the previous year, the total amount of time spent diving decreased, and during the expedition week, divers spent a total of 52 hours in the cave.

The reason for this is that the Dolans Yugraten cave requires longer dives to reach the end of the line, whereas the other caves in the area are relatively short. In Cold Hollow, 311 feet of passages were mapped in the direction of Dolans Yugraten, making it the most promising area for the 2020 expedition. As for the map links of all the caves in the Beeralvin Valley, Bureaucraten remained unchanged at 984 feet in 2019, while Dolans Yugraten remained unchanged at 7,879 feet.

Cold Hollow had a length of 731 feet, while Spago Groton and Semigrotten D3 had a length of 531 feet. Although mapping data from 2019 was lost, Bestin’s cave had been explored earlier and had a length of 213 feet.

Challenges Faced and Resuming Exploration

Despite the progress made so far, the team faced some specific challenges during their expedition. One of the divers experienced an issue with a leaking glove, which they managed to safely exit the cave from despite a small hole. Additionally, another diver accidentally activated the position finder in SOS mode, prompting the dive leader to notify a safety diver to locate them. Once the situation was resolved and the position finder was switched to the correct mode, the dive continued as planned.

Furthermore, a miscommunication between dive buddies and poor visibility in a section of the cave resulted in their separation, but the first diver to the surface was able to quickly return and find their mate within 10 minutes. The team also encountered three accidents involving snowmobiles in the first few days when snowfall made the track more difficult to navigate. Fortunately, no individuals were injured, and the snowmobiles sustained no damage.

After enduring several years of the COVID-19 pandemic, the team was finally able to resume their cave exploration in the Beeralvin Valley in 2022. The feeling of being back and able to pursue several leads, including Festens Cave, as well as exploring new ones such as Iskaratan, also known as the Ice Cave, was exhilarating. Having been away from the project for three years, the team considered it a major success to be back in action.

2022 and Future Expeditions

For this expedition, the team utilized the same equipment as before, consisting of a Lake Aviva GS-15 Rover mounted on a two-meter-tall carbon fiber pole and an Aleka CS-10 field computer provided by the Swedish lant material. They once again used their GNSS equipment to measure points, which were tracked using Bose tracking devices. Their objective for the year was to concentrate on exploring the Ice Cave and Feston’s Cave. In the previous year, they were able to surpass a small obstruction in Feston’s Cave and discover a larger passageway with a current on the other side. They planned to pursue this lead but realized that it would require significant effort to clear out the sand and gravel that blocked their path, both at the cave entrance and the obstruction from the previous year.

Despite having done a lot of digging previously, they knew that the water flow in the cave would replenish the same areas with fresh sediment. To reach Feston’s Cave, they obtained special permission to use snowmobiles and had to cross a river. However, this year the river was not frozen, which meant they had to construct snow ramps on each side to cross, causing a one-day delay in setting up camp. Having a shovel with you is crucial in Beeralvin for tasks such as clearing snow, making snowmobile tracks, and removing underwater gravel. Once they established their camp and created a snowmobile track, they were able to enter the water.

Once they established their camp and created a snowmobile track, they were able to enter the water. Safety was a top priority, and the initial divers focused on widening the first passage by moving sand to the sides. Beyond the first passage, the cave extends for 180 feet before reaching a site passage. If you proceed straight, you’ll arrive at another entrance by traversing. If you turn left, you will reach the second restriction after a few meters. Before removing the gravel from that passage, the restriction measures about 9 to 16 feet. The primary restriction is at the bottom where the current is strongest.

After a few days of work, they were able to create enough space to pass through. The cave opened up, allowing them to continue up the slope where they positioned a localization beacon that could be detected from the surface. They came across a slightly wider tunnel and continued upstream. Although there was also a small path downstream, the downstream path had little or no current, so they didn’t prioritize exploring it, but it might be something to investigate further on their next expedition. They were able to advance a little further but encountered another obstacle, which is currently the end of the line due to the strong current.

Although there are still some leads, they are narrow and quite constricted. The current plan is to return in 2023 and attempt to extend the exploration of the cave with the expectation that it may be linked to the Meander cave. On March 30th, 2022, the group visited Is Groton, also known as the ice cave. It’s located near the junction of Lil Alvin Little River and Buralvin. They reached the cave by snowshoeing from the base camp at Feston’s Cave.

The group consisted of Lost Loquest, Ola Loafquist, and Magna Strom Hall. The cave is easy to locate in winter if you are familiar with the surrounding area. In the summer, it’s situated in an opening in the forest on a plateau with steep slopes surrounding it. The ice cave has two entrances, but they are currently constricted by ice, preventing passage between them.

The entrance furthest from the summer pathway provides access to the lower parts of the cave, and there’s a sturdy tree next to it that is perfect for rigging a rope to gain access to all known parts of the cave. About 98 feet of rope is required to enter the cave. The rope is rigged on a nearby tree, and one can rappel down using SRT gear. The cave is relatively clean and covered mainly in ice, so a full cave suit may not be necessary. However, it is recommended to wear crampons or remain connected to the rope at all times as it is quite slippery and there is a risk of falling.

In 2022, the team discovered that about 70 to 105 cubic feet of ice had melted away since their last visit in 2019. As a result, they were able to abseil down almost straight to the bottom of the cave. The rocky bottom of the cave is now easily accessible, whereas before it was barely reachable.

During their 2019 visit, the team found a reindeer skeleton in a corner that had slid down in a funnel of ice. This year, they observed that the ice surrounding had disappeared, allowing for a closer examination. It’s challenging to determine the amount of ice remaining in the cave since the shape of the cave beyond the ice is unknown. A rough estimate suggests that there’s currently between 353 and 1059 cubic feet of visible ice.

The scallops and formations on the roof of the cave suggest that the two cave entrances are ancient swallets. As you move further down into the cave, the walls become sharp and edgy, and there is a significant amount of debris at the bottom, indicating that frost wedging may have caused the cave to collapse, potentially obstructing its continuation. To find out more, ice must melt. With the climate getting warmer, the cave will likely be worth revisiting in just a few years.

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What is the Buralvin karst region?

The Buralvin karst region is the longest underwater cave in Sweden, located in the northern part of the country.

How were the caves in the Buralvin valley formed?

The caves were formed over hundreds of thousands of years by the gradual dissolution of calcium in the limestone deposits due to the seeping river water.

Who discovered the entrance to the Buralvin cave?

Bo Leander discovered the entrance to the Buralvin cave at the bottom of Lake Dolincion in 1979.

What are the goals of Expedition Bieralvin?

The goals of Expedition Bieralvin are to explore, map, and document the caves in the Buralvin Valley, raise awareness about the caves in the region, and collaborate with universities for scientific research.

What challenges do the cave explorers face?

The cave explorers face challenges such as treacherous conditions, heavy equipment, the risk of hypothermia, and the need for safety protocols and risk analysis in the remote mountainous and sub-arctic region.

Patrick Broin
Patrik, a seasoned cave diver, shares his first-hand experiences and expert insights on the treacherous world of cave diving accidents.
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