But the ash and smoke plume that had caused cancellation of flights and air traffic chaos across Europe..
..has dropped to a height of about 2 km (1.2 miles), the Meteorological Office said.
Ash production had fallen and Iceland's coast guard and scientists prepared to fly over the volcano in search of signs its crater was now producing lava, which could indicate the nature of the eruption was changing.
"The situation is definitely better than it was particularly on Saturday, which was a difficult day for us due to heavy ash fall just south of the volcano," said Urdur Gudmundsdottir, a spokeswoman at the foreign ministry.
The appearance of lava could suggest the eruption was moving into a less explosive phase, possibly a good sign for thousands of travelers who have been stranded at airport across Europe for the past five days because countries have closed their airspace over safety fears.
"Lava would be good because then we would not get all this ash, and we know what the ash is doing to the flights," Hjorleifur Sveinbjornsson, a geologist at the Meteorological Office, told Reuters.
Visibility near the Eyjafjallajokull glacier was almost nil as falling ash saturated the air and covered agricultural fields with a thin layer of dust which could be dangerous to animals if eaten, local media quoted the police as saying.
There was a risk, however, that molten rock could create new pathways for water to run into the crater, causing more explosions and a higher level of ash production.
The ash plume, which has cost airlines millions of dollars per day in lost revenue, had descended to a lower altitude as strong winds continued to push the cloud southward, he said.
"The ash plume is very low. It's not much higher than 2 kilometers," Sveinbjornsson said.
The column of ash rising from the volcano was as high as 11 km when it started erupting earlier last week.
Air traffic over Europe remained severely disrupted on Monday.
