Strýtan

Days run out of Hjalteyri, a small pier settlement about half an hour up the west side of Eyjafjörður from Akureyri, and the run out to the cone is short. The dive itself is planned tightly: down a fixed line to the top, a circuit or two of the upper flanks in the 20 to 30 m band, then back up the same line with the guide setting the turn rather than the group. Wind funnelling down the fjord decides whether the boat goes at all, so schedules stay loose and are usually confirmed the same morning.

What makes it strange is the mixing. Geothermal freshwater leaves the vents at somewhere around 70 °C, pouring out at roughly a hundred litres a second, so the column shimmers and smears like heat haze over tarmac and a hand moved across a vent goes from cold to warm within the span of a palm. The cone is soft mineral crust, clay and anhydrite rather than hard rock, which is why divers are kept off it entirely. Buoyancy control matters more here than any other skill.

Divers only found the cone in 1997 and protection followed quickly, first for the cone in 2001 and then for the smaller chimney cluster nearby in 2007. Around them the fjord fills out the rest of the day with shallower, slower dives where the interest is on the bottom rather than the geology above it, and a macro lens earns its place. It suits divers who want something structurally odd and are content with green fjord water, and most build a trip around a few days in Akureyri rather than a diving week.