B737-800
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
General Evacuated
Aircraft; Environment - Non Weather Related
Aircraft was nearing completion of boarding. I was on flight deck when smoke began entering cockpit via all vents. Simultaneously; #1 FA quickly entered flight deck asking what was going on. I turned to look back into cabin and was unable to see past First Class seats as smoke quickly filled cabin from ceiling down to seat level. I informed FA to perform an Emergency Deplaning via jet bridge only because I felt evacuating on ramp with weather conditions and lack of armed evacuation slides would be dangerous; also flight had light load and conditions (smoke) forward were in my opinion better. I acted to isolate smoke entry into cabin by closing APU Bleed and shutting down APU; also closing Packs 1&2. When event began; Captain was in restroom; but he quickly entered into the decisions upon entering flight deck; initially leading us to the Evac checklist which was halted when it was apparent the event was leading away from an effective conclusion via the checklist. The Captain and I reaffirmed the course of action taken was best with the information available and we both believed we had effectively isolated the issue to the best of our abilities. The Captain switched his attention rearward and began assisting in cabin with the completion of the deplaning; while I began coordinating outside responses. The aircraft in question had been at the gate for over 12 hours in sub zero temperatures; was ice covered; and had not been deiced recently. We had not begun the deicing procedures prior to smoke event.
B737-800 First Officer reported evacuating the passengers through the jet bridge when the cabin began to fill with smoke while the aircraft was still at the gate.