Weather forecasters today signalled a no-flight order imposed here amid fears over the volcanic ash cloud will ease tomorrow evening.

Aviation chiefs have closed Irish airspace until 6pm today and warned that the no-fly order imposed because of the Iceland volcanic ash cloud looks set to run until the end of the week.

The eyes of geologists, disaster officials and sightseers are today focused on Mount St Helens, where a mix of volcanic gases and low-level earthquakes raised fears the mountain in Washington state might blow its top at any moment.