A group of surfers recently rode waves for a distance of nearly five miles in Alaska. For most surfers, a really long ride might last about 20 seconds and cover 50-60 yards.
The 5 mile journey took place at Turnagain Arm in the Cook Inlet near Girdwood. The reason why theses long waves occurred is a phenomenon called a tidal bore, caused when the leading edge of an incoming tide pushes against an opposing current or the direction of a river. This creates actual tidal waves.
Tidal bores occur in very few places around the world. Surfers often try to predict when this will happen. They can ride the waves but with traditional surfboards it's difficult to stay on them for the duration, because they can suddenly diminish before building again. However, the invention of larger standup boards, on which surfers use a paddle for momentum , has maximized the Turnagain bore experience.