Madison Bowey, Rourke Chartier and Tyson Baillie also scored for the Rockets, who erased a three-goal deficit and a 4-2 score after 40 minutes of play to comeback and take Game 1 of the Western Conference final.
Kirkland and Baillie added two assists apiece for three-point outings.
Oliver Bjorkstrand scored twice for the Winterhawks and Keoni Texeira and Chase De Leo had the others.
Jordon Cooke made 22 saves for Kelowna while Portland's Brendan Burke kicked out 31-of-36 shots in a losing cause.
OIL KINGS 8 TIGERS 3
EDMONTON — Cody Corbett had a pair of goals and Curtis Lazar added a goal and an assist as the Oil Kings pumped Medicine Hat in Game 1 of the Eastern Conference final.
Griffin Reinhart, Luke Bertolucci, Brandon Baddock, Dysin Mayo and Brett Pollock also scored for Edmonton, which used a five-goal second period to pull away.
Curtis Valk extended his point streak to nine games for the Tigers by scoring twice and Alex Mowbray had the other.
Tristan Jarry made 28 saves for the Oil Kings. Marek Langhamer allowed five goals on 22 shots for Medicine Hat while Nick Schneider let in three goals on eight shots in 6:22 of relief.