Diving Silfra has been on my bucket list since I became a diver, and it was one of the primary motivators for our trip to Iceland in the first place. In order to really understand why Silfra is such a special place however, you need a little information on the area and the geologic processes that are occurring there. Silfra is more than just a crack in the ground full of the clearest water in the world. It is located in Þingvellir (pronounced thing – vet – leer) National Park, a site which rests on the Mid Atlantic Ridge.
When most people think of the Mid Atlantic Ridge they assume it is found at the bottom of the sea, and they are usually right – but here in Ísland, the same hotspots and volcanic activity that created the island have brought the bottom of the ocean right to the surface, making Þingvellir a highly unusual landscape. Around Silfra you can the see the Mid Atlantic Ridge jutting up from the ground, and the tectonic activity that is occurring in the park is pushing the European plate and the North American Plate apart roughly an inch per year.
The ground in and around Þingvellir is, quite obviously, composed of volcanic rocks which act as an excellent natural water filter. The water in Silfra originates some 25 miles or so to the north and comes from Iceland’s second largest glacier. At some point in the past, lava flows cut off the meltwater’s overland route, forcing the water to percolate through the porous lava rocks in order to reach its final destination in Þingvallavatn lake. According to the dive master, it takes the water somewhere between 50 and 100 years to make the complete journey, meaning our dive took place in water that last saw the sun during the first world war or so! The springs that form the lake also create a current that pushes you throughout the dive, making it more of a sit-back-and-enjoy-the-dive experience and less of a get-out-there-and-explore dive. If anything, you might want to flare out and slow yourself in the current to really enjoy it all. The natural filter and the current result in amazing water clarity, possibly the best in the world.
From a temperature standpoint it is important to realize you are diving in meltwater runoff at a latitude of about 66 degrees north, so it is not surprising that the water temperature is roughly 1-3 degrees Celsius (33 -36 Fahrenheit). The local divers joke about another, more technical description of the water temperature, but I will leave it to the reader to determine what terms they used to describe the temperature of the water (hint: not appropriate for children).
To combat the cold and ensure you survive, you dive in a dry suit so that only your face and hands are exposed to this water – and they go completely numb in about 2 minutes, so no worries there. About 5 minutes into my dive my suit developed a leak in the right wrist due to a stitching issue in the suit, so I also got to experience that cold water on my arm, armpit, side, hip, and foot. Refreshing is one term you could use to describe the water, but I may have used others. The water added a bit of weight to my right side and tilted me a little in the water, but it was not a serious enough leak to warrant aborting the dive. To compensate for the lopsided tilt I was experiencing I used my BC to control my buoyancy and only kept enough air in the suit to prevent squeeze, and that worked no problem.
Important point: if you are planning on diving here, make sure you have done more than one or two dives in a dry suit, as this is not a place to work on your skills, it is a place that requires skill. The current and especially the cold make this a demanding dive, and you don’t want to add a lack of ability in the dry suit to your task loading list. Dry suits are aggravating enough when you are first getting used to them, and I am by no means an expert dry suit diver, but the dives I had in advance prepared me to deal with the leak, and that really saved my dive experience here – shout out to Instructor Clay and SeaDragon Scuba for getting me ready to go. In short, be prepared!
The dive itself was amazing: flying is an apt description because the water clarity is so great that it is difficult to judge distances and depth of field. I didn’t lose the blue colors until I hit something like 15 meters (45 feet) depth! The lava rocks are stunning, the green algae (the only life I saw in the dive) is eerily beautiful, and the clarity of the water is truly unreal. The Cathedral, one of the deepest points the dive, concludes with a sweet slope of sand that allows you to see the light change from a greenish hue at the bottom that divers are used to seeing on their dives back to the blue hue Silfra is known for. I can’t recommend this dive enough, and as of this writing it is the most amazing dive I have been on so far.
Check out the video and let me know what you think!