There is currently no ice on Öskjuvatn, the crater lake of the volcano Askja in the northeastern highlands, which is unusual for this time of year. There are two possible reasons: increased geothermal activity or a snow-light winter; scientists lean towards the first option.

A screenshot from the website of Vatnajökull National Park.

“Usually Öskjuvatn is covered in ice until the summer, June or July,” Björn Oddsson, a geologist at the University of Iceland’s Institute of Earth Sciences, who flew with the Icelandic Coast Guard across the area on Monday, told mbl.is.

Pictures of the lake taken by Hreinn Skagfjörð Pálsson, a flight attendant at Air Iceland, in late March, which were published on the website of Vatnajökull National Park, caught the attention of scientists.

“There is something unusual going on, either a weather-related phenomenon or there is increased geothermal heat in the lake,” Björn stated.

The Coast Guard’s airplane with which he flew, TF-SIF, is equipped with heat cameras and they were used in the search for increased flow of heat.

“We didn’t see anything on the surface and it didn’t seem as if there was increased geothermal heat around the lake,” he said.

“So there are two possible reasons for [the lake’s iceless state]: increased flow of heat from the geothermal area below the lake or a winter with little snow and strong southwesterly winds,” Björn reasoned.

However, as he pointed out, Lake Mývatn, which lies lower than Öskjuvatn but in a similar area, currently has an ice cover. Therefore, geothermal heat is the more likely explanation, he concluded. Further research is necessary to confirm his suspicion.

Öskjuvatn in summer. Photo by Páll Stefánsson.

As to whether a volcanic eruption in Askja could be coming up, Björn replied that there are no indications of an immediate eruption but that scientists will look into the possibility, among other methods by reviewing data on seismic activity.

Björn pointed out that before the last eruption in Askja in 1961, increased geothermal heat was noticed in the area. Therefore the crater lake’s iceless states gives scientists reason to monitor the volcano closely.

He added that as Öskjuvatn is one of the deepest in Iceland, approximately 220 meters, significant geothermal heat is necessary to heat it up enough to cause all the ice on its surface to melt.

Click here to see Hreinn’s photos of the iceless crater lake and here to look at it from outer space, where in satellite photos from April 2 Öskjuvatn looks like a hole in the otherwise snow-covered northeast Iceland.

ESA