© NASA/Goddard/MODIS Rapid Response Team NASA's Terra satellite flew over the Eyjafjallajokull Volcano, Iceland, on May 6 at 11:55 UTC (7:55 a.m. EDT). The Moderate Resolution Imaging Spectroradiometer instrument known as MODIS that flies onboard Terra, captured a visible image of the ash plume. The plume was blowing east then southeast over the Northern Atlantic. The satellite image shows that the plume is at a lower level in the atmosphere than the clouds that lie to its east, as the brown plume appears to slide underneath the white clouds.
The authority said shifting winds, currently coming from the north, had bundled recent days' erupted ash into a massive cloud that is growing both in width and height by the hour.
Eurocontrol, which determines the air routes that airliners can use in and around Europe, says the ash accumulation is posing a new navigational obstacle - because the cloud is gradually climbing to 35,000 feet (10.5 kilometers) and into the typical cruising altitude of trans-Atlantic aircraft. Until recent days, the ash had remained below 20,000 feet (6 kilometers).
The Irish Aviation Authority said the engine-wrecking ash would skirt Ireland's western shores Friday, forcing a half-dozen airports to ground flights for much of the day. However, the airports in Dublin, Cork in the southwest and Waterford in the southeast will remain open.
"The restrictions are required as the increased level of recent volcanic activity has created a massive ash cloud stretching 1,000 miles long and 700 miles wide," the authority said in a statement.
The latest alert came only hours after British and Irish authorities declared the all-clear after much of the same ash was blown southwest from Scotland through Ireland on Tuesday and Wednesday, closing airports all along the way. Those were the first European air closures since the initial April 14-20 crisis, when ash from Iceland's Eyjafjallajokul (pronounced ay-yah-FYAH-lah-yer-kuhl) volcano forced authorities across Europe to ground 100,000 flights and 10 million passengers.
Eurocontrol, the continent's air traffic management agency in Brussels, also announced Thursday it plans to reroute flights between Europe and North America to avoid flying over the ash cloud off Ireland's west coast.
Until Eyjafjallajokul stops its emissions, the key to the future course of Europe's ash crisis will be the prevailing Atlantic winds.
When they blow to the northeast toward the unpopulated Arctic - the typical pattern in springtime - the danger to aircraft is minimized. But when they shift southward, as is happening this week and in mid-April, airlines' ability to land and depart safely is jeopardized.
The Irish Aviation Authority said trans-Atlantic aircraft using Irish air space were already giving the ash cloud a wide berth by shifting their flight paths south.
The volcano, about 900 miles (1,500 miles) northwest of Ireland, has shown no signs of stopping since it began belching ash April 13. The glacier-capped volcano last erupted sporadically from 1821 to 1823.
pumice... maybe one mile thick... that's 1.03E+17 cubic feet... say one milligram of ash per cubic foot... well, that's about 100 million tons of levitating ash.
Oh, sure.
And all that dust would likely settle out of the air somewhere soon - right? Wrong!!!