Seattle broke open a close game with three goals in the third period to hand the Tri-City Americans a 4-0 loss Friday at ShoWare Center in Kent.
Thunderbirds goalie Taran Kozun posted his second consecutive shutout, registering 26 saves. He has not allowed a goal in 125 minutes, 54 seconds.
Seattle (27-14-2-3, 59 points), which has won five games in a row, got a goal and an assist from Jaimen Yakubowksi, and three assists from Shea Theodore.
Tri-City, which got 27 saves from rookie Evan Sarthou, was shut out for the third time this season.
Despite the loss, the Americans (20-21-2-2, 44 points) were able to stay one step ahead of the ninth-place Prince George Cougars, who suffered an 8-0 home loss Friday to the Edmonton Oil Kings.
Parker Bowles returned to the Americans lineup after missing 16 games with a knee injury.