Trenton Howard rushed for 207 yards and two touchdowns and the Bruin defense pitched a shutout in the rain in White Salmon.
A scoreless first half ended with a missed field goal attempt by Columbia.
But the Bruins broke through just 23 seconds into the third quarter with Howard running in from 18 yards out.
The Bruins sealed the win with Howard’s second TD run — this one from 26 yards — with 51 seconds to play.
Columbia-White Salmon rushed for 249 yards and only attempted one pass in soggy conditions.
Cesar Isordia led the Bruins with 11 tackles. Hunter Harmon added added 10 and Chandlor Bucklin and Dom Raether had nine each. Alarick Blankenship had a forced fumble and a sack.
COLUMBIA-WHITE SALMON 14, SETON CATHOLIC 0
Seton 0 0 0 0– 0
CWS 0 0 7 7–14
CWS — Trenton Howard 18 run (Cesar Isordia kick)
CWS — Howard 26 run (Isordia kick)
RUSHING — Seton Catholic: No report; Columbia-White Salmon: Howard 19-207, Isordia 2-14, Austin Charters 11-16, Chandlor Bucklin 3-12.
PASSING — Seton Catholic: No report; Columbia-White Salmon: Charters 1-1-0-1.
RECEIVING — Seton Catholic: No report; Columbia-White Salmon: Bucklin 1-1.