At least 41 flights have been cancelled in Alaska after the eruption of Mount Pavlof.
A massive ash cloud has risen to 20,000 feet creating a no fly zone in the region.
A spokesperson for the University of Alaska Geophysical Institute said the volcano is known for having brief but explosive eruptions with little or no warning.
"If you look at some of the seismic data that we have, the intensity really ramped up pretty fast. It was quite abrupt."
Alaska Airlines has cancelled flights from six cities in northern Alaska
Volcanic ash is a significant safety issue for aircraft both on the ground and in the air.
Alaska Airlines have said they won't fly until the ash has cleared.
More than 3000 passengers have been grounded by the flight cancellations.
Mount Pavlof is located 965km southwest of Anchorage, Alaska.
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