More than a year after an Icelandic volcano wreaked havoc for millions of air travelers across the globe, a new eruption has spewed an ash plume 12 miles in the air. Iceland's airports have been shut down, and ash could affect Europe later this week.

Ash could reach northern Scotland by Tuesday and parts of Britain, France and Spain by Thursday or Friday if the eruption continues at the same intensity, airlines were warned on Sunday.

The warning is based on the latest 5-day weather forecasts, but is being treated cautiously because of uncertainties over the way the volcano will behave and interact with the weather.

The Grimsvotn (GREEMSH-votn) volcano, which lies beneath the ice of the uninhabited Vatnajokull glacier in southeast Iceland, began erupting Saturday for the first time since 2004, sending ash, smoke and steam 12 miles into the air.