Simplify the following text for a Grade 12 native English-speaking person.
Original: ( 28 ) Since then on April 19 , 2010 , many of the WWE Raw superstars were stranded in Belfast due to the ash cloud from EyjafjallajÃ kull ( a volcano in Iceland ) hovering over most of Europe and causing many flights to be put on hold .
Simplified: Since then on April 19 , 2010 , many of the WWE Raw superstars were stranded in Belfast due to the ash cloud from EyjafjallajÃ kull ( a volcano in Iceland ) hovering over most of Europe and causing many flights to be put on hold .