Mountain View returned two fumbles for touchdowns in the first quarter as Heritage miscues powered the Thunder to 56-12 win Friday at McKenzie Stadium.
The Thunder (7-1, 4-0 3A GSHL) clinched the outright 3A Greater St. Helens League title with the win.
Jaden Brown and Cameron Magnussen both returned fumbles for touchdowns as the Thunder built a 42-0 lead in the first quarter.
Cash Cook threw touchdown passes to four different receivers.
Heritage got its first touchdown on offense all season when Evan Buckman scored on a 3-yard run in the third quarter. Luke Melvin later scored on a touchdown pass from Owen Daley.