Air carrier Flight Attendant reported an external smoke event emanating from the ground power connection during gate arrival. Crew and passengers deplaned the aircraft and airport response vehicles arrived.

Narrative

We had landed; disarmed the doors; and started to deplane. I handed paperwork to the Captain and at this point Rows 1 and 2 had deplaned. All of a sudden; I saw the Captain run out of the flightdeck; panicked; and go down jetway stairs to the outside. I looked out into the jetbridge and could smell a very heavy smoky odor. I looked into the flightdeck and noticed the windshield was covered in smoke. I couldn't see through it. It was very thick. The smell was overwhelming. I said to the F/O (First Officer) 'what is that; is that fire? Should we evacuate; should we blow the slide in the back?' No answer. I asked again a few times. He then said 'no don't. There's a fire but we can't locate it.' I called the 'B' to inform her that there was a fire but we are not to blow the slide because we can't locate it per the F/O. The Ops Agent stuck her head into the galley and said 'get everyone off NOW.' I got on the PA and said Evacuate evacuate evacuate. Everyone off now; leave your things. The 'C' then grabbed the megaphone from the front galley and started to tell everyone to get off. People were still moving very slowly. I then got on the PA and said 'we need to get everyone off; fire fire fire.' The Captain returned to the flight deck. Once everyone deplaned; I got the remaining bags left behind by the passengers and put them in the jetbridge. The OPS Agent came on and told me that when they connected ground power to the plane; it started to spark and they couldn't get it disconnected. I then noticed two fire trucks had arrived when I looked out the forward galley service door window. At this point neither of our pilots addressed us nor debriefed us. We gathered our things and waited in the terminal for them but they never came.The Captain should have communicated with me as the 'A' FA. If he was not able to; the F/O should have assumed command. Afterwards; I would have expected a debrief after an event such as this one.