JEFFREY BROWN: But first: the volcano spreading trouble around the world.
Ray Suarez begins from London.
RAY SUAREZ: The Icelandic eruption is putting on a show, even out in space. Satellite images show the vast spread of the dust and ash over the North Atlantic and the skies of Northern Europe. Heat from Earth's engine, always running, is pumping a mix of material into the atmosphere, a violent push that started deep under Iceland, in a year full of them, with an earthquake, setting off a chain of effects more than 1,000 miles away.
Friday saw more than 17,000 flights canceled, roughly two-thirds of the air traffic in European airspace on a normal Friday, stranding hundreds of thousands in major gateway airports, like London Heathrow, Schiphol in Amsterdam, thousands of miles away in Delhi, India, and still further away in Singapore.
The drifting ash and dust is aimed directly at commercial aviation's operating zone, moving east at an altitude of 20,000 to 36,000 feet in what's normally some of the world's most crowded airspace. The world's airlines are expecting to lose $200 million every day the airport closures continue.
Flights from London are canceled through Saturday morning. Government meteorologist Derrick Ryall says his agency is taking regular looks at the vast volcanic cloud.
DERRICK RYALL, Met Office, United Kingdom: What we really want to know is what the plume is actually doing, where is it now, and how high is it, things like that. And it's very difficult. There are not many observing systems.
So, for example, if you have got low cloud, you can't see it from below. If you've got high cloud, you can't see it so easily from satellites. So, at the moment, we're trying to look at a whole range of measurements to try and pin it down.
So, for example, we're still using satellites. There's a research aircraft that's been deployed. I think it's going up this afternoon to try and find the plume, measure it, and try and get a sense of what sort of concentrations, what sort of material is in it. We're deploying what we call lidar. It's essentially some sort of radar which looks upwards from the ground.
And measurements so far have show some ash at higher levels. Once you have got that -- sort of those observations and measurements, they can help calibrate what we're doing in terms of predictions. And then you can make a better assessment of the risks to aviation.
RAY SUAREZ: Closing the skies to travelers set the dominoes tumbling down here on the ground. And whether you were headed to one of the British ferry ports or to the train stations that service the runs that cross underneath the British channel to the continent, every seat on every departure was full, at least until tomorrow night.
It's a reminder, there are only so many ways off an island. But travelers we spoke to, suddenly faced with an unscheduled British vacation, kept their good humor, and, so far, their patience.
WOMAN: We were here for business for two days. And, yes, now we're stuck here and get can't out of the country.
MAN: I'm traveling with a group of students. So, I have to consider other things than just myself.
RAY SUAREZ: Bigger names than Maria and Sven face travel woes. Polish officials are worried the air traffic disruptions will stop or slow the progress of foreign dignitaries heading to the country for the funeral of President Lech Kaczynski.
At University College London, volcanologist Peter Sammonds drills, smashes, and heats volcanic stone -- these samples are from Mount Saint Helens in Washington -- to understand what's going on deep in the Earth. The drama of these latest eruptions is caused by Iceland's unique mix of volcanoes and glacial ice.
PETER SAMMONDS, professor, University College London: The most recent vent has formed in an -- under an icecap, so the -- the magma is moving up and blasting through an icecap, thus melting the ice, producing lots of meltwater.
The meltwater is reacting very violently with -- with the magma. And that is sort of fragmenting it and creating -- creating this very, very fine ash, which is then being ejected very high into -- into the atmosphere. So -- so, this is sort of the unusual aspect of it. Otherwise, it's, you know, a reasonably moderate-sized sort of volcanic eruption.
RAY SUAREZ: There's no way of knowing how long a swathe of the Northern Hemisphere will have to contend with Iceland's blowing off steam.
DERRICK RYALL: This particular volcano has been going off for about -- since the March 20th. It's been erupting at a fairly low level. And it was only a couple of days ago that it erupted big-time, got up to about 20,000, 30,000 feet, so, that's a lot of ash, and then caught the winds at high levels that -- and, by chance, at the moment, the winds are just carrying it straight across towards the U.K.
RAY SUAREZ: And when will the cloud dissipate enough to lower the risk of catastrophic jet engine damage?
PETER SAMMONDS: It's an engineering judgment, sort of what sort of concentration of this volcanic ash actually is necessarily -- makes it necessary to shut down an airspace, and how much of that should be tolerated by -- by an aircraft.
RAY SUAREZ: But, for the moment, nature is reminding humankind that plans and systems and schedules sometimes have to give way to a planet that runs on its own clock.
And, as Britain was paying close attention to its first ever televised prime ministerial candidates debate, that striking cloud provided a political cartoonist with, as the title read, an obvious hot air metaphor too good to miss.