Ash disrupts flights in Scotland, Ireland

A new wave of dense volcanic ash from Iceland snarled air traffic Wednesday in Ireland and Scotland, strandingtens of thousands of travellersand threatening to spill into England's airspace.

Ireland's key hub, Dublin Airport, admitted defeat for the day and cancelled all flights until 4 a.m. Thursday, marooning more than 30,000 passengers in the process.

More than a dozen other airports throughout the Republic of Ireland, Northern Ireland and Scotlandshut down, too,as unseasonal winds pushed the gritty volcanic ash southwest back towards the Atlantic rather than northeast into the unpopulated Arctic.

Clouds of volcanic ash from Iceland prompted aviation officials to close airspace over a large swath of Europe for six days last month.

The ash cloudforced airlines to ground more than 100,000 flights and left as many as 10 million passengers stranded for days.

Ash not expected to reach London

Britain's Civil Aviation Authority said Wednesday's ash threat might reach northwestern England and Wales but would miss the four major airports of London.

Authorities are seeking to stop flights only when the ash reaches certain density levels and gets within 100 kilometres of an airport's path for landings and takeoffs a stark contrast to last month's closures of air services throughout several countries.

In Scotland, Glasgow Airport shut Wednesday but its eastern neighbour, Edinburgh, stayed open until midday.

Aviation chiefs in Ireland and Britain said they were updating their closures and reopenings within minutes of receiving updated ash maps every six hours from the Volcanic Ash Advisory Center in England.

The rapidly changing situation obliged would-be fliers to hop on trains, buses and taxis to reach nearby airports. Virgin Trains also launched extra services Wednesday between Scotland and London.

Market-leading airline Ryanair sought to discourage passengers dashing from airport to airport by announcing blanket closures Wednesday for Scotland, Northern Ireland and Dublin.

Ryanair also warned customers planning to fly out of several airports in the west and north of England Bristol, Leeds, Liverpool, Manchester and Newcastle to check the company's website and remain alert for possible closure announcements.

Directions too vague, critic says

Scotland's leader, First Minister Alex Salmond, slammed the Civil Aviation Authority for issuing a vague, inaccurate statement overnight that resulted in unnecessary flight cancellations in eastern Scotland, including Edinburgh and Aberdeen. He said the CAA had apologized to him.

"That can't be allowed to happen again. Press statements must be clear and not cause confusion," Salmond said.

Donie Mooney, operations director at the Irish Aviation Authority, said the volcano's emissions changed over the past few days and caught forecasters off guard, forcing Ireland to abandon its hopes of staying open Wednesday.

"The ash plume has been going higher and the ash is of a coarser nature. That threw our projected opening times into some disarray," he said.

Still, the ash clouds are remaining below six kilometres, far lower than the cruising altitude of passenger jets, therefore they pose a danger only to ascending or descending aircraft.

European co-operation

The renewed volcanic-ash threat in the skies of Britain and Ireland this week has tested the more precise safety rules adopted by European aviation authorities following the unprecedented closure of most northern European airspace.

European Transport Commissioner Siim Kallas and transport ministers from the 27-nation European Union agreed Tuesday at an emergency meeting in Brussels to press ahead on plans to unify their divided air-traffic-control networks.

Kallas said Tuesday that had last month's sweeping safeguards been imposed, "a very large part" of Europe would have lost its air links again and for days, not hours.

In Iceland, authorities said poor weather Wednesday was obscuring their view of the volcano and preventing coast guard aircraft from flying over the volcano. Civil Protection Coordination Office official Agust Gunnar Gylfason said the volcano's seismic activity has been unchanged in recent days.