Icelandic volcano could cause massive flooding

This item in the news recently. The link goes to a video that has neat pictures.

Icelandic volcano could cause severe flooding scientist warns

Hundreds of metres under one of Iceland's largest glaciers there are signs of an imminent volcanic eruption that could be one of the most powerful the country has seen in almost a century.
Mighty Katla, with its 10km-wide crater, has the potential to cause catastrophic flooding as it melts the frozen surface of its caldera and sends billions of gallons of water surging through the east coast and into the Atlantic ocean.

...The last major eruption occurred in 1918 and caused such a large glacier meltdown that icebergs were swept by the resulting floods into the ocean. The volume of water produced in a 1755 eruption equaled that of the world's largest rivers combined.