Rochdale 3 Grimsby Town 1
Howe, on as a substitute after Lee Thorpe picked up a first-half dead leg, survived a half-time ticking-off from his manager to double his Dale goal tally.
The early stages offered a promise of frustration for Rochdale as first of all Thorpe and then Adam Rundle hit the same upright and skipper Gary Jones saw his goalbound effort cleared off the line by Nick Fenton.
Ciaran Toner then hit the woodwork for the visitors with a wickedly curling free-kick on 37 minutes, but the game was effectively ended as contest when young striker Nathan Jarman picked up two yellow cards in five minutes and was dismissed six minutes before the break.
Howe opened the scoring within five minutes of the re-start when he headed home from close range and added a second via the post eight minutes later.
Dale then almost paid for failing to press home their obvious advantage when Grimsby substitute Andy Taylor headed home with five minutes to go and his side pressed forward in search of an unlikely equaliser.
Howe ensured the points and his treble deep into time added-on when his shot on the turn squirmed through the grasp of Mariners keeper Phil Barnes.
A fourth straight win moved the home side above Wycombe Wanderers in the play-off race while, at the same time, ended any lingering hopes that the visitors might have had of a top-seven place themselves.