Where Fire Meets Ice – The Icelandic Eruption

By: Melanie Hackett

Humans have always been fascinated by the immense power of volcanoes. After all, volcanoes are responsible for the birth of new earth, as is rapidly happening on the Big Island of Hawaii. In fact, the gases released by volcanoes may have contributed to the creation of our atmosphere, and therefore set the stage for all of life itself.

Here in the Yukon, these spewing beasts of fire have helped shape the landscape. Have you ever driven the Klondike Highway to Dawson and wondered about the white layer on the sides of the road, especially visible near Carmacks? That is volcanic ash, or tephra, from a massive eruption of Mount Churchill 1300 years ago. Near Fort Selkirk, at the confluence of the Yukon and Pelly rivers, Volcano Mountain is a young and active cinder cone.

But what happens when volcanoes erupt in frigid areas full of glaciers, and how does that change the landscape afterwards? In 2010, a team of scientists from the UK and Iceland set out to the flanks of Eyjafjallajӧkull to discover the consequences of fire meeting with ice.

Remember this Icelandic eruption? Yes, it’s the one that caused the greatest air travel disruption since the Second World War as ash clouds blanketed Europe. However, Eyjafjallajӧkull provided the opportunity for scientists to learn how volcano-driven torrents of glacial meltwater would behave and how they would alter the landscape.

When the volcano rumbled to life on April 14, 2010, it melted large amounts of ice, sending cascades of meltwater roaring down the mountain. These glacial outburst floods are given the easily pronounced name jӧkulhlaup. The action culminated in two larger floods that sent the equivalent of 60 thousand Canada Games Centre swimming pools down the flanks of the volcano! The surge flowed both underneath and atop the glacier, carrying gravel and debris into a lake at the base of nearby Gigjӧkull glacier. And before you can say “Eyjafjallajӧkull”, the lake level rose by nearly five metres, engulfing the scientists’ equipment. The jӧkulhlaup continued its rampage, smashed through the far lake wall and drained the lake entirely.

Before this, not much was known about what happens as these catastrophic floods are raging down volcanoes. The scientists’ time-lapse imagery showed another subsequent 140 jӧkulhlaups. Each of these is believed to have occurred after the rupture of temporary blockages in meltwater rivers. These floods were much smaller than the initial two because the increasing tephra created an insulating layer on the ice, so less could melt. However, what the scientists discovered, to their surprise, was that contrary to previous belief, the large floods did not actually transport the most debris. The 140 smaller jӧkulhlaups had a much greater influence on the new shape of the land, as they brought fans of gravel down the mountain.

These findings will be invaluable for future hazard assessment, especially since more and more of these glacial outburst floods are expected in our warming climate. Closer to home, a future jӧkulhlaup is possible at Lowell Lake, a sediment-dammed lake at the headwaters of the Alsek River. Currently there is not enough water in the lake to flood Haines Junction if a catastrophic flood were to happen, but as Lowell glacier melts into the lake with global warming, this could be of concern in the future. However, as Eyjafjallajӧkull has shown us, it is not necessarily the largest and most powerful body that initiates change. There is strength in numbers, and change can be initiated by much smaller forces, that when combined, hold great power.

Here in the Yukon, these spewing beasts of fire have helped shape the landscape. Have you ever driven the Klondike Highway to Dawson and wondered about the white layer on the sides of the road, especially visible near Carmacks? That is volcanic ash, or tephra, from a massive eruption of Mount Churchill 1300 years ago. Near Fort Selkirk, at the confluence of the Yukon and Pelly rivers, Volcano Mountain is a young and active cinder cone.