Travelers flock to flights as floods and slides shut down highways and Amtrak train service south and east from Seattle

With major highways closed and Amtrak train service between Seattle and Portland shut down Thursday because of flooding and slides, flights are the main way to get out of Seattle for those who need to travel south or east.

Regional carrier Horizon Air said it’s getting “exceptional demand” for flights between Seattle and Portland. It added six extra flights Thursday between the two cities and expects to add more flights on Friday. Interstate 5 and the rail line that link the two cities are closed because of the severe flooding near Centralia; the freeway could be shut for days and it’s not clear when Amtrak will be able to restart service.

All of Washington’s mountain passes across the Cascades also remained closed Thursday because of avalanche danger, cutting off road travel from the Seattle area to Eastern Washington (unless drivers take a long detour north and east through British Columbia).

Most of the demand for air travel is south to Portland, and Horizon is offering a “flood special” fare of $119 one way between Seattle and Portland through Saturday. (That fare may not be available on all flights; the regular fare starts at $149 one way.)

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“We also got a desperate call from Amtrak. They’ve got 250 people they need to get to Portland,” said Horizon spokeswoman Jenn Boyer. The airline was able to add extra flights Thursday to transport them and other stranded travelers, adding six flights to its normal 25 weekday flights.

Flights between Seattle and Portland also are available on SeaPort Airlines, a new regional carrier that departs from Seattle’s Boeing Field. It has about nine flights a day between the two cities, and had a handful of seats available Thursday afternoon.

Service between Seattle and Spokane on Amtrak’s Empire Builder train also was canceled Thursday, but seats were available on normal flights between the cities.

Kristin Jackson: