Iceland, Vattnajökull ice cap is a pressure cooker valve

Two rainy days during our fifteen days in Iceland means that we have been lucky, especially in September. But yesterday ended very wet, and also this morning it was pouring. We just had our breakfast when all cell phones in the restaurant of Smyrlabjörg Hotel started to beep. It was a general SMS alert broadcast from Iceland's Met Office, for everyone in the area, with the following text:

“During the last 24 hours, the level of the Skaftá river at Sveinstindur has risen significantly. These observations suggest that a glacial outburst flood (jökulhlaup) is in progress.
It is likely that the flood originates from the western Skaftá ice cauldron, which last drained in June 2015; however this is unconfirmed until visual observations are made.
The discharge of Skaftá at Sveinstindur is presently 270 cubic metres per second. The flood is not expected to cause any downstream disruption, although the following points should be kept in mind.
Hydrogen sulphide is released from the floodwater as it drains from the Vatnajökull ice-cap. The gas is particularly potent at the ice margin, where concentrations will reach poisonous levels. Travellers must stay away from the edges of Skaftárjökull and Tungnaárjökull while the flood occurs.
Crevasses will develop rapidly around the ice cauldron, so travellers on Vatnajökull should stay away from the region.”

We looked at each other, and then out of the window: the tiny waterfall behind the hotel was unrecognizable: we now saw that it was at least three times as wide. That morning we stayed in the hotel. We played cards in the restaurant and had a pretty darn lot of coffee.

Iceland, Höfn, eastern Vattnajökull glacier tongue

One of the local waiters explained to us how to understand the SMS message:

"Vattnajökull is the largest glacier and ice cap in Europe. It does not just cover mountains, these mountains are volcanoes. Because at least three of these are more or less active volcanoes, when one of the volcanoes becomes unquiet, a lot of water at the bottom side of the glacier melts. This water accumulates in cauldrons, deep inside and underneath the glacier.

The pressure in these cauldrons rises with the temperature, and this effect may get stronger by warming from above (temperatures, lots of water above freezing point, landing on the glacier area). When the locked in water heats up, and pressure rises even more, something has to happen.

Compare the ice cap with the safety valve of a pressure cooker. When the pressure inside the kettle reaches a certain point, the valve will open and there will be a release before it closes again. Exactly this is now happening with the ice cap. The pressure underneath is so high that the ice cap is liften for a short while, and there is a puff-out happening right now. We call this a "Jökulhlaup", a glacier run.

In the case of Vattnajökull, even a slight temporary opening of the lid means an eruption of an enormous quantity of water, steam and sulfur loaded gas (hydrogen sulfide, or "rotten egg gas"). This natural but toxic gas (H2S), which is always present in volcanism, is now escaping in such high quantities, together with the water, that people must stay away from the swollen rivers, especially where it just appears from under the ice. Otherwise you can be killed."

He reassured us that this does not mean that a real volcano eruption is coming up anytime soon. There is some outburst building up, we know that because seismic activity is indeed growing, but a real outburst could still stay away for years.

After lunch the rain stopped, and the afternoon was mostly dry. My girlfriend wanted t take it easy and didn't feel like going out today, but I wanted to buy a certain book about the birds of Iceland. After promising that I would stay away from stinking swollen rivers, I drove to the nearest little town, which was about 40 kilometers to the east: Höfn. In a shop next to the visitor's center I found what I was looking for.

Iceland, Höfn, eastern Vattnajökull glacier tongue

Iceland, Höfn

Iceland, Höfn

Iceland, Höfn

Iceland, Höfn

On the way back, I could add another species to the list of wildlife that we had seen. In the grass land I spotted a reindeer. He was not impressed about me looking at him, because of the distance, but probably also because I was just by myself.

Iceland, Höfn, raindeer?

Iceland, Höfn, reindeer!

In the 40 kilometer to Höfn and the same distance back, I did not see a single other car, except on the land strip on which Höfn is situated.