What is it about the thought of undersea walls that makes divers get that far-away look in their eyes? Perhaps it’s because the walls are so often awash with nutrient-rich currents full of life, making them a photographer’s paradise. Maybe it’s because the need for pinpoint buoyancy control and deep diving skills leads walls to be labeled “advanced dive sites,” which lends them an allure in and of itself. Or it may just be that swimming along a wall gives the sensation of flying above the very edge of the abyss…

Whatever the reasons, divers travel all over the world to experience the best walls the oceans have to offer. As diverse and wonderful as California is, there are not many places here that can compete with the scope and scale sites like Cayman’s Bloody Bay Wall. But there are a few, and one is Scripp’s Canyon just north of San Diego.

Here, ancient sandstone sea cliffs formed when the sea level was much lower are now sheer walls that descend hundreds of feet to the ocean floor, forming a northern branch of La Jolla’s vast submarine canyon.

The sheer walls of Scripp’s Canyon bear the scars of eons of erosion that started when the cliffs were formed and continued after they sank below sea level. Ravines cut back deeply into the face of the cliffs. Where these clefts extend upward to the top of the walls, they are filled with frozen cascades of sand. The deep crevices and looming overhangs offer shelter to abundant fish life. Schools of rockfish lurk in the shadows, while sheephead and blacksmith forage around them. Gobys occupy the smaller crannies and scorpionfish perch on the ledges. The cold upwellings attract rarer species for Southern California, such as wolf eels.

Invertebrates seem to love these walls almost as much as divers. Nudibranchs are prolific and some species that are rare elsewhere are seen quite commonly at Scripp’s. Sponges and gorgonians provide a colorful backdrop to the scallops, Christmas tree worms, barnacles, anemones, and tunicates that extract their sustenance from the currents.

Like any wall dive, Scripp’s Canyon demands excellent diving skills and careful planning. The wall starts at about 80 feet, so it is possible to dive the site within no-decompression limits. However, the depths dictate that divers pay extremely close attention to bottom time, depth and gas consumption.

In addition to the depth, divers should also be prepared for a cold, dark dive. The upwellings that cause the walls to flourish often bring the temperatures down to the low 50s and even 40s. A dry suit is recommended. Even though visibility is often good in the canyon, poor visibility nearer the surface can cut down the light at depth so much that a good light and a backup light are absolutely required.

Getting to the canyon is almost as much of a challenge as the dive itself. The dive can be accomplished as a beach dive, but it requires a grueling hike from La Jolla Shores (south of Scripp’s Pier) followed by a lengthy surface swim.
It is far more practical to conduct the dive from a boat. However, the advanced nature of the Scripp’s means that there is insufficient demand for San Diego dive boats to run regular open boat trips to the site. Fortunately, there are six-pack boats available for charter to Scripp’s and some of the bigger dive boats will occasionally visit the canyon when the conditions are worthwhile.

Once you have reached the site, locating the canyon is relatively easy. The head of the canyon is marked with a buoy that is tied off at about 70 feet. As you drop into the canyon at this point, the walls are less than 20 feet apart. But as you swim on and the floor drops away, the walls soon diverge and the diver has to chose which one to follow.

Scripp’s can be approached as an out-and-back dive along the wall, which allows divers to use the line of the marker buoy to assist with their ascent. Alternatively, shore divers can ascend to the top of the wall at about 80 feet and follow the natural contour of the sand up toward the beach. Whichever return trip is planned, divers at Scripp’s should be prepared to complete an open-water ascent (possibly in limited visibility), if necessary.

These factors mean that this dive site really deserves its “advanced” rating. But, for those divers who are prepared to cope with the challenges, Scripp’s Canyon is wall-to-wall fun.