Parade just went past Queen's - how long until this crowd actually drains and we can move

On a Kumbal night the procession itself is often past a given corner in under an hour after 6:40. The police then unwind street by street. Dalada Veediya / lake front can stay pedestrian-only into the late evening. If you can still hear the whip and the hevisi, stay put - walking into the route is how people get shouted at. When the last torch line has gone and the police tape starts to droop, then move with the flow, not against it.