Hawkair DH8C at Terrace on Apr 7th 2014, gear did not retract and multiple other warnings

A Hawkair de Havilland Dash 8-300, registration C-FIDL performing flight BH-113 from Terrace,BC to Vancouver,BC (Canada) with 19 people on board, was climbing out of Terrace when the crew received multiple warnings, the master caution illuminated together with an outboard spoiler indication. The gear did not retract with a #2 hydraulic isolation valve caution light, the crew verified the gear had not retracted. The crew climbed the aircraft to 15,000 feet to escape turbulence and icing conditions while working the checklists. The crew worked the emergency checklist and the alternate gear extension checklist, declared emergency and returned to Terrace for a safe landing about 55 minutes after departure.