Islands nonstop volcanic ash across Europe. A cloud of ash from the volcano stopped spewing Iceland air traffic over a wide swath of Europe on Thursday, aircraft grounding on a scale unseen since the 2001 terrorist attacks, authorities halted all flights on England, Ireland and the Nordic countries. Thousands of flights were canceled, blocking thousands of passengers and officials said it was unclear when it would be safe enough to return. One aviation expert said it was the first time in memory a cloud of ash that had some of the most challenging airspace of the world’s most congested, while scientists in Iceland, said the issue of volcanic ash and interference in air traffic could continue for days or even weeks. “Today may be impossible to say when we resume the flight,” said Peter Henrik Joergensen, spokesman for the airport forCopenhagen in Denmark, where about 25,000 passengers were affected. The ash cloud that rose from 20.000 to 36.000 meters feet (6,000 m and 11,000 m), located on the Atlantic Ocean near the flight path for most roads in the East Coast of the United States to Europe. The cloud pushes south and east in the United Kingdom, the country banned the air traffic control of all non-emergency flights until at least 07.00 clock (0600GMT, 2 Clock EDT) Friday. Irish authorities closed their airspace for at least eight hours, and aviation authorities in Denmark, Norway, Sweden and Belgium has the same precautions.