The seas around Indonesia’s Nusa Tenggara archipelago are among the most unpredictable and dangerous in the tropics.

This is the area where the Indian and Pacific Oceans meet, where cold water wells up from the abyss, creating a mosaic of tidal races and whirlpools. There is little boat traffic, save for local subsistence fishermen and the occasional ferry. For a lost diver drifting at the surface, it is a vast and hostile environment.

Divers visit these islands because all that roiling water brings nutrients that power one of the world’s richest eco-systems. Komodo Island – famous for the endemic giant lizards known as Komodo dragons – sits at the heart of the archipelago, and has some of the best dives in South East Asia.

For the travelling diver in search of the world’s most exciting destinations, it is an obligatory stop. I’ve been there twice myself, and while the colour and diversity of the reefs was astonishing, I was even more awestruck by the power of the currents that define these seas.

If you are diving in this area, chances are it will be from a safari boat or liveaboard sailing out of Bali. These vessels in turn use support boats – usually fast skiffs or inflatables – which are used to deposit the divers in high-energy areas, then pick them up one by one as they surface.

But Komodo plays tricks on divers: unlike the placid drift dives of the Caribbean, different currents can converge and separate. There are even eddies here that can propel a diver downwards, known as “down-currents”.

All of this is safely navigable for experienced divers, but Komodo is no place for novices. If divers are separated underwater, it can be hard for the boatmen to follow their bubbles. Ideally, the should be carrying marker buoys to indicate their positions, but if a boatman gets distracted, a seven or eight knot current can quickly carry the divers out of sight.

At that point, the search has to broaden and other vessels must be called in to help. I know what it’s like waiting at the surface in these seas.

The water is surprisingly cool, and as the hours go by it has a weakening effect, sapping heat away far quicker than air. Even as the cold sets in, they will be also suffering from the effects of sunburn, as the equatorial sun here is unforgiving. They will at least have the benefit of lifejackets, as all divers wear buoyancy-compensating devices that can be filled with air. I only hope the seas there are calm, as the relentless buffeting of waves will also take a toll on their energy, and could split them up.

Sharks are undeniably a worry, especially with the growing paranoia and feeling of helplessness that comes when you’re drifting at the surface. However, many of the big sharks in this area have been fished out for the shark fin soup industry.

The only dangerous species around Nusa Tenggara are the oceanic white-tip and the silky sharks, both ocean-going predators with a natural sense of curiosity. I never saw any of these sharks during my dives there; in this instance, the water is the primary threat.

In such circumstances, the only course of action is to try and stay together, huddle for warmth and wait for help. Any depletion of their energy could hasten the onset of hypothermia, so there’s no point trying to swim against a current.

That said, there is every chance they may have been swept into the path of one of the many uninhabited islets in this remote place; we can only hope this is the case.

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