Aerial images of the Skáftárketill calderas shows that the eastern of the two calderas has grown significantly, indicating increased geothermal activity under the glacier. The outburst flood earlier this fall came from the eastern of the two calderas. The flood was more powerful than any on record. Yesterday the Icelandic Civil Protection Agency declared the end of alert phase due to the flood.
Met Office instruments destroyed or washed away
Authorities are still evaluating the damages caused by the flood. The local news site visir.is reports that the flood washed away many of the measurement instruments used by the Icelandic Meteorological Office to monitor the river and possible floods.
Read more: See aerial photographs of the dramatic glacial outburst flood as it sweeps away roads
A larger flood raised concern, questions
Glacial outburst floods are caused by meltwater bursting from beneath the glacier. Geothermal activity under the glacier melts the ice which collects in calderas. The weight of the ice above keeps the meltwater locked in the caldera, but when the water level has reached a point where the water pressure manages to lift the glacier the water bursts from underneath the glacier.
Usually floods from the eastern of the two Skáftárketill calderas come once every two years, but this year‘s flood came full five years after the last one. The long delay between floods indicated less geothermal activity underneath the glacier, thus slowing down the melting, or alternatively that the caldera had grown, allowing more water to collect between floods. The size of the flood and the new images point toward the second explanation.
The eastern caldera has grown
Yesterday, at an information meeting for residents near the flood, Tómas Jóhannesson a glacier specialist at the Icelandic Meteorological office revealed that the caldera has expanded in all directions, but especially to the south. The expanded caldera can hold much more water than the old one. Tómas also argued the most likely reason for this expansion is an increase in the geothermal activity under the glacier.
According to Tómas it is too early to say whether future glacial outburst floods from the Skáftárketill calderas will be as large as this year‘s flood. The activity under the glacier could return to its previous pattern, but it was also possible it would continue to increase and that longer time would pass between floods, making them even larger.
Aerial images of the Skáftárketill calderas shows that the eastern of the two calderas has grown significantly, indicating increased geothermal activity under the glacier. The outburst flood earlier this fall came from the eastern of the two calderas. The flood was more powerful than any on record. Yesterday the Icelandic Civil Protection Agency declared the end of alert phase due to the flood.
Met Office instruments destroyed or washed away
Authorities are still evaluating the damages caused by the flood. The local news site visir.is reports that the flood washed away many of the measurement instruments used by the Icelandic Meteorological Office to monitor the river and possible floods.
Read more: See aerial photographs of the dramatic glacial outburst flood as it sweeps away roads
A larger flood raised concern, questions
Glacial outburst floods are caused by meltwater bursting from beneath the glacier. Geothermal activity under the glacier melts the ice which collects in calderas. The weight of the ice above keeps the meltwater locked in the caldera, but when the water level has reached a point where the water pressure manages to lift the glacier the water bursts from underneath the glacier.
Usually floods from the eastern of the two Skáftárketill calderas come once every two years, but this year‘s flood came full five years after the last one. The long delay between floods indicated less geothermal activity underneath the glacier, thus slowing down the melting, or alternatively that the caldera had grown, allowing more water to collect between floods. The size of the flood and the new images point toward the second explanation.
The eastern caldera has grown
Yesterday, at an information meeting for residents near the flood, Tómas Jóhannesson a glacier specialist at the Icelandic Meteorological office revealed that the caldera has expanded in all directions, but especially to the south. The expanded caldera can hold much more water than the old one. Tómas also argued the most likely reason for this expansion is an increase in the geothermal activity under the glacier.
According to Tómas it is too early to say whether future glacial outburst floods from the Skáftárketill calderas will be as large as this year‘s flood. The activity under the glacier could return to its previous pattern, but it was also possible it would continue to increase and that longer time would pass between floods, making them even larger.
