The Grimsvotn volcano erupted Saturday in Reykjavik, Iceland. This is Iceland's most active volcano and it has forced the closure of the main international airport and all domestic flights have been cancelled. Last year, ash clouds from another Icelandic volcano, Eyjafjallajokul led to the closure of a large section of European airspace, with repercussions for flights from the U.S. Matthew Roberts from the Iceland Meteorological Office has been monitoring the erupting volcano.

Mt. Saint Helens erupted thirty years ago today. For the Takeaway's John Hockenberry, this was the first natural disaster he witnessed and it started his career as a reporter. He remembers back to a time when the idea of an erupting volcano seemed outlandish.

From airlines champing at the bit to get back in the air over western Europe despite Iceland's volcanic ash, to some dirty dealings at Goldman Sachs, questions of risk and risk-taking are dominating the news cycle this week. But what happens if we avoid risk all-together? Is it even possible?

European officials struck a deal yesterday to reopen most of Europe's air space to plane travel as early as this afternoon, assuming Iceland's Eyjafjallajokull volcano continues to subside. This would end the worst peacetime travel disruption in history, a travel crisis that has left thousands of passengers stranded for days and cost the airline industry hundreds of millions of dollars. But in the midst of the chaos and inconveniences, one philosopher took a moment to reflect on what our world would look like without airplanes.

Among the passengers stranded by the volcanic ash wreaking havoc on European air travel were a group of geek philosophers from all over the world, in London for a forum on social entrepreneurship. One of them decided to capitalize on the chaos and he setup an impromptu conference under the banner of the TED conference of ideas: TEDxVolcano.

Travellers caught up in the air transport chaos in Europe caused by a cloud of volcanic ash from an Icelandic volcano are going to extraordinary measures to get home. British travelers trying to get to the U.K. will soon get help from an unlikely source: The British Government has announced that two major war ships will come to the rescue for stranded British nationals in Spain.

We take look at what's ahead this week, with Marcus Mabry of The New York Times and Latoya Peterson editor of the blog, Racialicious. Volcanic ash continues to keep most European flights grounded affecting attendance at everything from the Major Economies Forum on Energy and Climate to the Tribeca Film Festival, both of which take place this week. Meanwhile, Washington is still buzzing about the Iran memo sent by Defense Secretary Robert Gates. And in cultural news, Wanda Sykes' show is up for renewal and Green Days' "American Idiot" opens on Broadway.

A five-mile high plume of ash from an erupting volcano in Iceland is drifting across Northern Europe, causing massive disruption at airports in the U.K. and Scandinavia. All flights originating from Scotland have already been grounded, and all London flights will be suspended.