Hawks soar to NWL East crown
Colvin connected for a solo shot in the bottom of the first inning to forge a 1-1 tie, then lifted a sacrifice fly in the third to put the Hawks (42-29) on top for good.
With the Hawks clinging to a 2-1 lead, Alfred Joseph and Josh Lansford started the fourth with singles. Steve Clevenger got down a sacrifice and reached on a fielder's choice. Lewis put the game out of reach with a bomb to left-center field.
Colvin added another solo blast, his 11th, in the first to make it 7-2.
Colvin, Lansford, Lewis and Mario Mercedes each had two hits. Matt Camp collected three of Boise's 13 hits.
Darin Downs (4-2) earned the win, striking out three in two perfect innings. Starter Jose Pina limited the Dust Devils (35-36) to one run on five hits in four frames.
The Hawks lost nine of their first 11 games before turning things around with a 21-6 run. The pennant clincher extended their winning streak to a season-high six games.
Boise will host the Salem-Keizer Volcanoes on Thursday in the first game of the Northwest League championship series.
Keith Weiser (1-2) suffered the loss, Tri-City's fourth in a row, after giving up seven runs on eight hits in five innings. He fanned five and did not walk a batter.
Michael McKenry went 3-for-5 with a homer, two RBIs and a pair of runs scored in the losing cause. Hector Gomez also collected three hits with an RBI and a run scored.
Zack Hample is a contributor to MLB.com.