DIVERS: Jan (OW, 43 dives), Hugh (OW, 32 dives) and Riad (DM, 1,277 dives)

SITE: Drift dive along a wall, South Pacific coral reef, 45 feet top of wall, 1,000-plus below

CONDITIONS: Visibility 100-plus feet, water temp 83°F

The group descended to 60 feet to begin its drift dive along a wall. The divers drifted at a leisurely pace, enjoying the sights, for about 15 minutes before they first noticed water pushing them downward. Continuing to drift, they passed 70 feet and the force increased. They added air to their BCs, which slowed but didn’t stop their descent. Kicking upward, they couldn’t rise. Hugh and Jan struggled harder, going nowhere, but Riad, also kicking to stay up, pointed away from the wall and signaled them to follow him. Kicking hard, their BCs almost full, the trio passed 100 feet swimming out from the wall. They felt the current dissipate after a moderate distance and, after a few more seconds of swimming, began to rise. Within moments, they were headed up, dumping their BCs to control the ascent. After a safety stop, they surfaced and the boat picked them up.

WHAT THEY DID WRONG

The trio didn’t do anything wrong. Downwellings are rare, usually localized and difficult to predict. The main mistake you can make is to dive in current along walls without staying alert for the possibility.

WHAT THEY DID RIGHT

They inflated their BCs, which, while not enough to overcome the current, still greatly slowed their descent. Hugh and Jan didn’t know what to do, but they didn’t panic, and wisely followed Riad, a seasoned professional, away from the wall.

5 TIPS FROM THIS INCIDENT

1. GEOGRAPHY DIRECTING current downward causes downwellings. Although they are rare, stay alert wherever currents flow along steep structures dropping into deep water.

2. WATCH FOR CUES. Fish swimming in place facing up the wall and soft corals bent and waving down the wall indicate a downward flow.

3. BUBBLES GOING DOWNWARD indicate a very strong flowing current.

4. AS WITH ANY CURRENT, you can’t outswim a downwelling. Just as you swim across a rip current to escape it, swim away from the wall, across the current. Most importantly, don’t panic.

5. IF IT SEEMS as if you’re unable to get out of a downwelling and your BC doesn’t have enough lift, drop your weights. A rapid ascent once you’re out of the current is better than being carried unwillingly to depth.

WANT TO READ MORE LEARN FROM THIS STORIES? VISIT THE TRAINING SECTION OF OUR WEBSITE.