A great odor of sulfur is arising...

In Iceland, the monstrous Katla volcano is rumbling, making the local Norse nervous.

The Katla volcano is invisible under the Mýrdalsjökull glacier, and it's eruptions are signaled by earthquakes and huge floods of melted ice water, called in both Icelandic and English a  jökulhlaup, that suddenly gush forth from under the ice.  That is happening in a small way now.

The Múlakvísl glacial river flooding (or would that be  jökulhlaupting?)  on Saturday.

The same river this morning

The glacial outburst flood at Múlakvísl in South Iceland has reached a peak on Saturday, but the river flow eased on Sunday.  Electrical conductivity is now measured around 580 µS/cm and has increased rapidly the last hour, according to an announcement from the Icelandic Met Office. People are warned to stay away from the area. 

A great odour of sulphur is rising from the river. The Iceland Road Adminstration is on standby to close the road. 

The alert level in Katla has been moved from green to yellow but nothing points yet to the likelihood of an eruption, although activity has increased. 

Katla is one of the largest volcanoes in Iceland. It is situated to the north of Vík í Mýrdal and to the east of the smaller glacier Eyjafjallajökull. Its peak reaches 4,961 ft and is partially covered by the Mýrdalsjökull glacier. The system has an area of 230 sq mi. The Eldgjá canyon is part of the same volcanic system.

The caldera of the Katla volcano has a diameter of 6.2 mi and is covered with 660–2,300 feet of ice. The volcano normally erupts every 40–80 years. The flood discharge at the peak of an eruption in 1755 has been estimated at 7.1–14.1 million cu ft/sec, comparable to the combined average discharge of the Amazon, Mississippi, Nile, and Yangtze rivers.

The 1918 eruption resulted in extending the southern coast by 5 km due to laharic flood deposits, or huge deposits of rubble from the very same Múlakvísl glacial river.

Katla's present dormancy is among the longest in known history.

A view of the Múlakvísl, looking towards Hjörleifshöfði in the background and the Atlantic Ocean.  Classic Iceland right there.