Oct. 10/14-The Jazz Aviation LP DHC-8-102 (C-GJMO), operating as flight 7789, had arrived in Sault Ste. Marie (CYAM) after a flight from Toronto (CYYZ). During deplanement at the gate the ground crew noticed smoke coming from the #2 engine (PW120A) and informed the flightcrew who ordered a rapid deplanement of the remaining passengers. The fire department was called and responded. It was determined the smoke was caused by fluid leaking from a ruptured hydraulic line near the exhaust. The line was repaired and the aircraft returned to service.