Volcanic ash stranded at least 5,000 travelers Sunday night and early Monday morning when a shift in the wind moved a giant ash plume into flight routes, causing Alaska Airlines to cancel 44 flights into and out of Alaska.
"The entire state is unflyable," Alaska Airlines staff told passengers at Seattle's airport Sunday, according to Chelsea Harms, an Anchorage woman who was booked on Flight 111 to Anchorage.
Alaska would add flights to try to accommodate the stranded passengers, according to Caroline Boren, Alaska Airlines spokeswoman.
Boren said Continental, Delta and United had cancelled some flights.
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A database of departures and arrivals at the Anchorage airport showed most flights this morning coming and going as scheduled, abut Borwn said the difficulty is at night, when pilots can't see the ash to avoid it. The airline will look at wind conditions tonight, then make a decision about grounding flights.
Alaska Airlines made the decision to halt flights after the National Weather Service issued a SIGMET (Significant Meteorological Information) warning for an area in Southeast Alaska near the Panhandle when the wind shifted to carry some ash into the Gulf of Alaska and some over the northwestern coast of Canada.
Kristi Wallace, a research geologist for the Alaska Volcano Observatory, said the wind sheared off part of a 40,000-foot ash plume from Kasatochi in the central Aleutians and carried it northeast from the North Pacific to the middle of the Panhandle.
Kasatochi erupted Thursday and is one of three volcanoes currently simmering in the Aleutians, along with Mount Cleveland and Okmok.
Seismic activity at Okmok picked up notably on Sunday, the observatory said, but it was the days-old ash plume created by Kasatochi's initial eruption that created headaches for travelers.
"The flight levels are going right through that SIGMET area, and that area is full of ash," Wallace said.