Askja Caldera and Askja Víti, Iceland

Askja Caldera is a subsidence caldera in the Highlands region of Iceland. Formed 10 thousand years ago, more recent eruptions have changed the landscape and allowed a stunning lake and smaller explosion crater to form. The smaller crater known as Askja Víti has a small lake which is geothermally heated and perfect for swimming in the right conditions.

Exploring Askja Caldera

Leaving the parking space at Vikraborgir behind the path through the lava field heads uphill to the lip of the caldera. A small incline with sharp chaotic lava abutting hills is coated in the remains of the winter snow. As the caldera comes into view the sheer scale of the area hits hard.

In the distance, the Dyngjufjöll Mountains can be seen on the northern side of the UNESCO Vatnajökull National Park. Rising to over 1000 metres they are an impressive sight. A path meanders across the caldera. More of a worn trail than a path, indistinct in places but the intermittent markers show the way whatever the conditions.

Despite being flat the caldera walls and the Dyngjufjöll Mountains give perspective to the area. The colours of the lava change as you progress across the caldera and snow clings in places even in the middle of summer. As you walk across the caldera look at the craters and rocks that pepper the walls. They each have a unique appearance and vary in size, shape and colour.

Askja is a 45km² subsidence caldera formed when the roof of a magma chamber collapsed after an eruption about 10 thousand years ago. Later small eruptions filled the caldera with ash and lava until a large eruption in 1875 threw pumice and ash into the caldera and the surrounding area.

Again the magma chamber roof collapsed and a new caldera formed. Over the next 30 years, the caldera was filled with groundwater and the stunning 11km² Öskjuvatn Lake was formed. This is the deepest lake in Iceland with a depth of 217m. At the same time, the smaller Víti explosion crater formed adjacent to Öskjuvatn Lake

Askja Víti

During the eruption in 1875, pumice was thrown from the crater and towards the end of the eruption a small eruption crater Víti was formed. This deep crater is located on the northeast shore of Öskjuvatn a water-filled caldera formed during the same eruption.

Víti means ‘hell’ in Icelandic and this vivid blue geothermal lake with boiling vents around its edge may well be the entrance. After walking across the barren lava fields Öskjuvatn comes into view before the hidden Víti crater is seen.

The path to the shore is steep following a river bed which even in good weather is slippery and difficult, but the rewards are worth the effort.

The water is pungent and murky. Bubbles rise to the surface as pockets of gas are disturbed, the smell of sulphur clinging to your hair, skin and clothes as a reminder of your visit for days. Despite the smell, the water is an inviting temperature. Perfectly heated by the volcanic rumblings just below the surface.

The shoreline is coated in crystals. All colours of the rainbow from deep blue to vivid orange. A chemistry lesson surrounds you as you stroll the short distance from the path into the crater to the small waterfall.

This may be one of the most beautiful and unique places to swim in Iceland.

Safety at Víti Crater

Before visiting the crater you really should speak to the rangers at Dreki. They will advise you on whether it is safe to walk out to the crater and what the water conditions are like. The walk takes 45 minutes each way and the weather can change in a moment. The rangers will be able to give advice and local knowledge.

The path out to the crater is marked but in poor visibility, it would be easy to wander off the path, if visibility does drop return rather than continue in the hope of not getting lost.

Walking down into the crater is very steep. In dry weather it is difficult but in wet weather, whilst you may get down into the crater coming back up would be impossible. If the rangers have put signs saying you should not go down into the crater then do as you are told!

Within the crater on the shoreline, there is a clearly marked geothermal area. It is difficult to miss as it is boiling away. There are signs in case there is any doubt about the boiling steam that it is constantly emitting. To the right of the path down, there is a small rope barrier. Stay to the left of this as there are constant rock falls from the crater walls.

Hiking Askja Caldera

There are clear trails and you can reach the caldera from the car park or by a longer walking route from Dreki. The rangers in Dreki can advise on routes and weather conditions.

When you reach the parking area there is a map with information about the routes and times, although these are just estimates. The walk across the caldera is clearly marked with yellow markers which you should follow whatever the weather and ground conditions. the path is indistinct and it is easy to wander off.

If you want to find out more or have company then there are daily guided walks across the caldera leaving from the car park.

Getting to Askja

Askja is not an easy place to reach. It is reached by driving across lava fields and ash from Ring Road 1 following either the F910 or F905 to Dreki and then continuing along the F894 to the Vikraborgir car park at the end of the road. Whichever route is taken at least four hours if not more is needed after leaving the ring road to get to Askja. A 4WD vehicle is essential as the road is rough and there are a number of river crossings to ford.

The road is not open all year round and conditions change rapidly so the local conditions should be checked. It is also best to check with the rangers at Dreki before continuing to Askja.

• Vikraborgir Car Park at the end of Road F894
• View on Google Maps
• See the trail map