The ice cave
Wisps of steam rose gently into the frigid air from between the water worn boulders in the melt water stream bed. Icy fingers hung from the roof, collecting the steam, condensing it, turning it into stalagmite droplets that sparkled in the glittering light of the head torches of the two geologists who were slipping over the boulders.
There was an eery stillness but the vaulted ice above creaked and banged as the stresses in the ice cap moved and eased under the weight of ice. It was snowing hard outside so the weight was changing, increasing, adding to the stresses on the corbal roof of the cave as it supported the immense weight above it. The roof was being weakened by the steam from the flank of Grímsvötn below, melting the arch above.
‘I thing Grímsvötn is waking up,’ said Siggi.
‘The last eruption was in 2004 so another is due this year and by the look of the steam from the fumeroles, it could be sooner, rather than later,’ agreed Arne.
They picked their way carefully through the treacherous stream bed while keeping a careful watch on the roof of the cave. A vast pile of smashed ice nearly blocked their way. It had clearly recently crashed down from the roof. They picked their way around the pile and pushed the route out to where the cave narrowed into tunnel, the roof and side closing in claustrophobically. The noise increased as they climbed further, the melt water crashing and leaping in the stream bed. The creaking and groaning from the roof of the tunnel increased in intensity. The boulders in the stream bed crashed together as they imbricated. There was also the feeling of dread, an underlying sub sonic hum. It felt like Grímsvötn was stretching and intending her muscles, ready to burst a stream of molten lava from the mountain, ready to tackle the melting of the ice cap to start a Jökulhlaup on its way across the Sandur outwash plains to the sea. ‘The land of fire and ice indeed!’
As Arne and Siggi wriggled their way up the tunnel, deeper into the ice, the water flow increased, scouring out the ice to the sides of the tunnel into phantasmagorical shapes, designed by the laws of physics and rheology, crafted by the non-Newtonian Reynolds flow of the water.
Ahead they could just see the molten lava erupting silently from one of the vents ion the floor of the cave directly into the cold rushing water. This instantly cooled the surface of the lava so forming the pillow lavas that can be seen over much of Iceland. SIG and Arne were enthralled by the sight which is probably why they lingered too long in the danger area and were overcome by the sulphurous gasses that were being emitted from the vents as the volcano started to erupt. The temperature in the tunnel started to rise very quickly, melting the base of the ice roof.
The roof started a progressive collapse. Massive volumes of ice quickly changed to liquid phase and added to the considerable flow in the stream, quickly converting it to a river and then shortly to a raging torrent that further undermined the ice resulting in further progressive collapses.
There was now a full Jökulhlaup in operation. It swept all before it as its flow volume reached that of the Amazon. The flow of course carried out the bodies of the two geologists. They were later found close to the sea, where they had been carried far out on the sandur. Their bodies were not recovered because the A1 road had been swept away and crossing the sandur was impossible in any sort of vehicle.
The eruption lasted only two days but in that time, many cubic kilometres of ice had been melted above Grímsvötn’s crater resulting in a deep depression in the surface of the ice cap, surrounded by many crevasses.
It took a week after the Jökulhlaup flow calmed down to reinstate enough of the road to allow traffic through.
It snowed regularly over the next few weeks, as if nature was covering up her gaping black wound on the ice cap.
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