Dallas Ehrhardt, Caleb Belter, Brett Roulston and Colin Jacobs had the other goals for Prince George (5-1-1). Erricson also added an assist.
Joey Leach, with two, Kyle O'Connor and Erik Benoit scored for Kootenay (1-5-0). Luke Philip picked up two assists.
Brett Zarowny made 35 saves for the Cougars in the victory. Mackenzie Skapski allowed four goals on 11 shots before getting pulled in favour of Wyatt Hoflin, who stopped 5-of-6 shots the rest of the way.
Erricson's first of the season came on a slapshot from the slot as the Cougars sent the Ice to their third straight loss.
After Erricson gave the Prince George the lead, the Ice had a great chance to tie it after Cougars' centre Zach Pochiro was handed a five-minute major for checking from behind.
But the Ice couldn't capitalize as Prince George held on.
The Cougars scored on their first shot of the night when Ehrhardt scored on a 4-on-2 rush just 70 seconds into the first.
Jacobs made it 2-0 on a breakaway with a pretty deke at 6:29 before Kootenay got one back when O'Connor scored his first WHL goal off a goalmouth scramble on the power play at 18:40.
Belter restored the Cougars' two-goal advantage 3:34 into the second, but Kootenay cut the lead again when Benoit bounced a low shot home at 5:56 and Leach tied it at 11:40.
Roulston then scored his first in the WHL to give Prince George the lead again at 17:20.
However, Leach scored his second of the night at 2:49 of the third to knot the score 4-4.