As the ocean water pushes upstream against the flow of the river, a tidal bore is formed. It can travel as far as 500 miles up the Amazon and on the rivers that flow into it. The boretide provides one of the many locations in Alaska to be in alignment with nature. The TA Surf company offers services and information to safetly and enjoyable recreate in the arm. Full moon so pretty impressive tide for such a huge ch... Moncton's riverside Tidal Bore Park provides an outstanding opportunity to witness a fascinating natural phenomenon - a tidal bore. Tidal Bore Moncton Surfing in Moncton, New Brunswick 691488702 We spent a few days in Moncton at the Chateau Moncton right on the tidal bore. Surfing A tidal bore, also known as a surge, is a massive and often single wave caused by the constriction of an incoming spring tide, as it gets funneled up a narrow and shallow river. Turnagain arm is the area in Alaska where the tidal bore creates a surfable wave.