The ash clouds from the Grimsvotn volcano in Ireland have forced airlines to cancel the flights across northern Britain on Tuesday. Hundreds of people will be grounded in Scandinavia and Denmark as the ash spreads.

The ash clouds from the Grimsvotn volcano would cover the Irish Republic, Northern Ireland, Scotland and parts of northern England by 0600 GMT on Tuesday, Britain's Met Office said in its forecast.

“About 250 flights have already been canceled and expects 500 flights to be canceled today,” Kyla Evans, a spokeswoman for Euro control, the Brussels-based agency that coordinates air traffic management across the region told local media.

U.S. President Barack Obama's left Ireland and arrived in Britain a day ahead of the scheduled date because of the ash cloud.

Airlines requested travelers, to verify their flights status online before leaving for the airport.

Europe with 30,000 flights a day is one of the world’s busiest airways.

Last year in April and May, the eruption of Iceland volcano, Eyjafjallajokull, grounded more than 100,000 flights in Europe, trapping millions of business and holiday travelers.