STOCKHOLM/REYKJAVIK (Reuters) - Iceland's volcanic eruption has died down and is no longer spewing out ash, officials said on Wednesday and airlines began to get back to normal after cancelling about 1,000 flights in northern Europe.
European air traffic agency Eurocontrol said it expected the ash cloud would dissipate overnight and did not see any significant disruption to travel in Europe on Thursday.
The explosion of the Grimsvotn volcano on Saturday caused much less chaos than an eruption last year at another Icelandic volcano thanks to new rules for airlines, but the incident showed problems remain with the regulations. Budget airline Ryanair was vocal in its criticism.
Hrafn Gudmundsson, a meteorologist at the Icelandic met office, told Reuters that mainly steam was coming from the crater, with no ash plume detected since 0300 GMT.
"There are indications that it's ceasing really," he said.
"At this stage we can at least hope for the worst to be over in terms of ash production," he said.
"At the moment there is practically no ash being produced and what little there is is being deposited on the glacier that is immediately around the crater."
After the eruption, the most powerful by Grimsvotn since 1873 and stronger than the one at Eyjafjallajokull that caused air traffic chaos last year, a massive plume of ash spread across northern Europe.
Flights in Scotland and northern England were canceled on Tuesday, while four German airports -- Bremen, Hamburg and Berlin's Tegel and Schoenefeld -- closed on Wednesday only to be reopened hours later.
Dutch airline KLM resumed flights to affected destinations after a brief break.
Eurocontrol said about 450 flights were affected in Germany following a similar number of disruptions a day ago across northern Europe.
"Tomorrow, we do not expect any significant impact on European airspace," it said.
Eurocontrol had earlier said the ash could drift to Poland, but a Polish air traffic control official said no traffic limitations were due.
The ash cloud from Grimsvotn belched as high as 20 km (12 miles) into the sky after the eruption, but did not trigger the kind of travel chaos caused by Eyjafjallajokull when more than 10 million people were hit by a six-day European airspace shutdown. That cost airlines $1.7 billion.
Grimsvotn's eruption did expose disarray among the authorities who decide on aviation safety as they try to apply new rules to avoid another mass closure of European airspace.
New procedures put the onus on airlines to make judgments on whether it is safe to fly through ash, in coordination with the forecasting authorities, particularly the Volcanic Ash Advisory Center at the British Met Office, and civil aviation bodies.
Sources told Reuters a British research plane designed to sample ash remained grounded for a second day in a wrangle over its deployment.
Ryanair on Tuesday said it had safely sent two planes into what authorities had deemed high ash zones over Scotland, and criticized "bureaucratic incompetence."
He called for the British authorities to use multiple sources of data when deciding on how to react to ash problems.
"The potential for a patchwork of inconsistent state decisions on airspace management still exists," IATA Director General Giovanni Bisignani said in a statement, calling on Tuesday for more coordination.
Grimsvotn is Iceland's most active volcano.
Though the Open University's David Rothery expressed optimism this eruption was over, he added: "However, it will be back - next week, next year, or more likely next decade."
(Writing by Simon Johnson and Patrick Lannin in Stockholm, additional reporting by Niklas Pollard in Stockholm, Tim Hepher in Paris, Kate Kelland and Avril Ormsby in London, Annika Breidthart and Eric Kelsey in Berlin, Philip Blenkinsop and Robert-Jan Bartunek in Brussels; Editing by Matthew Jones)