Surfers know the answer to at least one of NCEX's basic questions even if no one quite understands the "why" part. Black´s Beach is one of California´s—and America´s—prime surf spots. Its epicenter is a 450-meter (1,475-foot) stretch called "Black´s Bowl," where riders from Japan, Australia, and other countries come to surf every year just so they can say they´ve been here.

The surf that gets them up in the morning is the product of shoreward-moving wave energy interacting with the complicated underwater bathymetry. When the water depth decreases to about twice the wave height, the resulting breaking waves can send currents flowing in several different directions. Along many coasts, there is a clear relationship between wave direction and the resulting currents. On a north–south-oriented shoreline with fairly simple bathymetry, such as that studied in a related project at Duck, North Carolina (See "Sand Wars," Winter 1995 Explorations), waves approaching from the north drive surf zone currents to the south, and waves from the south drive currents to the north.

But on this complex coastline dominated by submarine canyons, rules about what´s typical go out the window. Through a process known as refraction, the deep waters of La Jolla and Scripps canyons form an effective barrier to waves approaching land. The result is that the energy is diverted away from the canyon head and focused in the locations that make Black´s Beach tube city for surfers. The energy creates breaks as high as five meters (15 feet) in autumn´s storm season and produces consistently rideable waves with good shape throughout the rest of the year.