Ash cloud , cancellation of number of flights , . This `` stickier '' magma caused a powerful explosion when it hit the volcano 's ice cap , resulting in smaller and sharper ash particles capable of traveling further and remaining airborne longer . Authorities have raised the threshold for flying in ash cloud . They say ash particles emitted by Grimsvotn glacier are less hazardous than those from Eyjafjallajokull .
Ash cloud , cancellation of number of flights , . Authorities have raised the threshold for flying in ash cloud . They say ash particles emitted by Grimsvotn glacier are less hazardous than those from Eyjafjallajokull .