Kerlingarfjöll: Iceland's Geological Rainbow

Deep in Iceland's central highlands, where volcanic activity has painted the landscape in impossible hues, Kerlingarfjöll stands as one of the country's most spectacular yet undervisited geological wonders. This mountain range, whose name translates to "Old Woman Mountains," presents visitors with a surreal tableau of rust-red rhyolite peaks, steaming geothermal fields, and mineral deposits that create a natural rainbow across the highland desert.

Located roughly 150 kilometres northeast of Reykjavík and accessible only via the challenging F35 Kjalvegur route, Kerlingarfjöll rewards the adventurous with landscapes that seem lifted from another planet. The range consists of several peaks exceeding 1,400 metres, with Snækollur (1,477m) claiming the highest point. What sets this destination apart isn't merely its altitude, but the extraordinary geothermal activity that has transformed the mountainsides into a painter's palette of yellows, oranges, reds, and purples.

The Geological Marvel

Kerlingarfjöll represents a textbook example of rhyolitic volcanism, where high-silica magma has created distinctively coloured rock formations over millennia. The mountains formed during the last glacial period, approximately 100,000 years ago, through a series of subglacial eruptions that created the distinctive flat-topped peaks characteristic of Icelandic table mountains.

The true spectacle lies in the extensive hydrothermal alteration zones scattered across the range. Steam vents, hot springs, and fumaroles have deposited minerals that stain the mountainsides in vivid colours. Iron oxides create the dominant rust-red and orange hues, while sulphur compounds contribute brilliant yellows. The interplay between ongoing geothermal activity and the underlying rhyolite bedrock has produced what many geologists consider Iceland's most visually striking highland landscape.

The Hveradalir geothermal valley, nestled between the main peaks, serves as the crown jewel of this geological wonderland. Here, dozens of hot springs bubble at temperatures reaching 85°C, while steam vents hiss continuously, creating an otherworldly atmosphere that's particularly dramatic during the cooler highland mornings.

Accessing the Highlands

Reaching Kerlingarfjöll requires commitment and proper preparation. The journey begins on the F35 Kjalvegur, one of Iceland's oldest highland routes, which connects the southern lowlands to the north through the uninhabited interior. This route typically opens in late June and remains accessible until September, though conditions vary annually based on weather and snow coverage.

From Reykjavík, the journey covers approximately 200 kilometres and takes 3-4 hours in a suitable 4WD vehicle. The route passes through the dramatic landscape change from green lowlands to the stark highland desert, crossing several unbridged rivers that can be challenging during periods of high water. The final 15-kilometre approach road (F347) branches east from the main F35 and requires careful navigation across rough terrain.

Highland buses operate during summer months, with services from Reykjavík costing around 18,900 ISK (€135) return. However, having your own vehicle provides significantly more flexibility for exploring the various hiking routes and geothermal areas at your own pace.

The Highland Hut and Base Camp

The Kerlingarfjöll Mountain Resort, operated by Ferðafélag Íslands (Iceland Touring Association), provides the only accommodation option within the mountain range. This highland hut complex offers dormitory beds from 7,200 ISK (€52) per night, private rooms from 15,800 ISK (€113), and camping spaces for 1,800 ISK (€13). The facility includes a restaurant serving hearty highland fare, with dinner menus typically priced around 4,500 ISK (€32).

The resort serves as an excellent base for exploring the area's numerous hiking trails and geothermal wonders. Staff provide detailed trail maps and current conditions, essential given the changeable highland weather. The facility operates from June through September, with exact dates depending on road conditions and weather.

Exploring Hveradalir

The crown jewel of any Kerlingarfjöll visit is the Hveradalir valley hike, a relatively accessible 6-kilometre return trek that showcases the area's most spectacular geothermal features. The trail begins from the mountain resort and follows a well-marked path through increasingly dramatic terrain.

The initial 2 kilometres traverse typical highland landscape before entering the geothermal zone, where the temperature noticeably increases and the distinctive sulphur scent fills the air. The final kilometre presents a maze of steaming vents, bubbling mud pots, and mineral-stained mountainsides that create the rainbow effect for which the area is renowned.

Safety remains paramount throughout this hike. The thin crust around hot springs can break without warning, and several areas require careful navigation around actively steaming ground. The trail typically takes 3-4 hours, allowing time for photography and careful exploration of the safest viewpoints.

Summit Challenges and Advanced Routes

Experienced hikers can tackle several challenging summit routes, with Snækollur representing the ultimate prize. The ascent covers 8 kilometres return from the mountain resort, with 600 metres of elevation gain across increasingly technical terrain. The route requires solid highland hiking experience and appropriate gear, as weather can change rapidly at altitude.

The Loðmundur peak (1,432m) offers a slightly less challenging alternative, with spectacular views across the Hofsjökull glacier and the broader highland plateau. Both summit attempts should only be undertaken in clear weather with proper navigation equipment, as thick fog can descend rapidly in the highlands.

Planning Your Highland Adventure

Kerlingarfjöll demands respect and preparation. Weather conditions can shift from pleasant hiking temperatures to near-freezing with driving rain within hours. Essential gear includes waterproof layers, warm clothing, sturdy hiking boots, and navigation equipment. Even summer visitors should pack winter-weight clothing for the highland environment.

The optimal visiting period spans July through early September, when road access is most reliable and weather conditions are relatively stable. Late June visits are possible but may encounter lingering snow, while September brings the risk of early winter weather closing access routes.

For those seeking Iceland's most dramatically coloured landscape away from the tourist crowds, Kerlingarfjöll delivers an unforgettable highland experience. The combination of challenging access, spectacular geology, and pristine wilderness creates memories that last long after returning to civilization. This geological rainbow represents Iceland's highland beauty at its most raw and magnificent.

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