If you live or work near Sea-Tac Airport, you may have noticed an increase in large air cargo jet traffic recently.

With the Anchorage airport intermittently closed due to ash fall from the Mt. Redoubt volcano, international cargo carriers are diverting their refueling stops to Sea-Tac, in some cases with three times more arrivals than normal, with more diversions expected if conditions persist.

During the first four days of the eruption, 45 cargo aircraft have diverted here, primarily large widebody 747 aircraft from three major Asian cargo carriers (Korean Air Cargo, EVA Air Cargo, and China Airlines Cargo). Normal operations for these carriers at Sea-Tac would see two to three air cargo arrivals per day or about 15 per week. However, the first four days of diversions (Mon.-Thursday, 3/23/26), brought 10 -15 arrivals per day, or nearly the equivalent of an entire week’s schedule for these international carriers. Sea-Tac staff is expecting another 30 or more diversions from these carriers in the next two days.

“Our staff is rising to the challenge to accommodate our cargo customers in this unusual situation,” said Sea-Tac Airport Director of Airport Operations Mike Ehl. “We are making every inch of our facilities available to keep the economic engine of goods flowing without an impact on regular passenger traffic.”

Anchorage is a major refueling stop for aircraft in an out of Asia. The volcano eruption has made it extremely hazardous for aircraft to arrive in Anchorage, thus, Sea-Tac has become the next closest refueling spot for these aircraft. These trans-Pacific cargo flights must refuel along the west coast to reach inland locations such as Chicago, New York, and Atlanta. The same is true in the opposite direction returning to Asia.

Overall, Sea-Tac receives 85-90 air cargo flights per week including domestic traffic. Sea-Tac Airport is ranked as the 19th largest airport in the U.S. in terms of cargo volume, with more than 290,000 metric tons shipped by air in 2008.