1996, Victoria Falls & white water rafting on the River Zambezi

Africans called them "the smoke that thunders". It is a name far more evocative of the power and grandeur of the Victoria Falls than that bestowed on them by a white man trying to ingratiate himself with a far-off monarch.

At this time of year the broad and hitherto placid Zambezi, swollen from seasonal rains, flows over the falls at a rate of 400,000 cubic metres a minute, crashing on to rocks 100 metres below. Nothing prepares you for such a sight.

Neither does anything prepare you for the enveloping welcome of the "creamy white buttocks", the post-imperialist nickname for a set of foaming rapids greeting those who choose to ride the river beyond the falls.

All that water, stretching across the 1km-long falls is concentrated into a narrow ravine, in some areas no more than 30 metres wide. Little wonder, then, that it was more than 100 years after the first European set eyes on the falls before anyone decided to explore how stimulating it might be to negotiate the rapids.

A group of rafting enthusiasts from Los Angeles decided to test them out in 1981. The group formed a rafting company, now operating from the Zambia side of the river.

Thus was born one more addition to what has become an almost bewildering range of stunts designed to produce adrenalin rushes for young people who have never heard an air-raid siren or the whine of a doodle bug.

Victoria Falls offers what has to be one of the world's top thrill-seeking assignments. First you can see the falls, then you must fly over them in a micro-light aircraft or helicopter. Finally you can ride the rapids. If that is not enough you can leave your brain at the hotel and leap off the bridge over the gorge attached by the legs to a 100-metre-long piece of elastic. People pay nearly £100 a time to do this. I settled for the rapids. Aficionados told me they were not as worrying at this time of year - just after the rains - as they were in the low water season. The huge volume of water has a cushioning effect on the rocks.

No one appeared to have told the crew of an accompanying raft as we swept down the first set of rapids and they were catapulted, en masse, into the foam.

All the rapids have nicknames. Beyond the buttocks were "terminator one" and "terminator two", and the "washing machine". The epithet "oblivion" was reserved for a particularly nasty set of rocks. Rapids, like rock-climbs, are graded for their degree of adversity up to six. The Zambezi river rapids reach a degree of 5-plus.

Safi, the head guide of Sheerwater Rafts, the biggest operator on the Zimbabwe side of the river, told us that we had two choices on the rafts. We could either have a passive role where an oarsman steered the boat and the occupants simply hung on, or we could each take a paddle, perch on the side, and do our bit to control it ourselves.

It was not an easy choice. I had been worried enough about the journey to pen some funeral instructions earlier that morning. Dylan Thomas's evocation, "Do not go gentle into that good night," seemed appropriate so I grabbed a paddle.

Our steerer, a burly Zimbabwian, nicknamed Hippo, partly because of his girth and partly because of his love of total immersion, told us he had no intention of going in the water. This was encouraging because I was sharing the raft with seven Australians from Telstra, the Australian state-owned telecoms group, one of whom seemed intent on getting a ducking. "Are we going to flip it?" he asked expectantly.

Now, I don't mind doing something with an element of risk, but when someone over whom I have no control is intent upon introducing an additional degree of recklessness, I become upset. I measured the thickness of my paddle blade against the gap between his chin and chest. If it came to it, I thought, a swiftly administered chop to the throat would do the trick.

The only drawback of sharing a raft with seven Australians is that they insist on entertaining you with a full compendium of the perils of living in Australia (even if they themselves rarely get out of the suburbs). This included the "red back" spider which hides under lavatory seats and bites your bottom (non-lethal), the "stingers" (lethal), venomous jellyfish which inhabit the seas around Darwin, the saltwater crocodile (incredibly lethal), which live among the stingers, and the funnel web spider (lethal and intelligent) which creeps into shoes and sleeping bags.

Apparently funnel webs have a memory. I heard of an occasion when one of their number, swiped away in an angry gesture, pursued its tormentor across a road, ran up his leg, and delivered the coup de grace.

None of these dangers seemed particularly immediate or relevant apart from the crocodiles. We saw small crocodiles on rocks by the side of the river. These had survived being washed over the falls.

My Australian companions, however, had more pertinent tales of terror. Colin, a veteran of white water rafting on the rivers Tully and Namoi, spoke of rapids so turbulent that they bent the front of the raft sufficiently to meet the rear. In those circumstances the occupants tended to be catapulted out as it straightened.

The stories could not have been closer to home. The indemnity form we signed before the trip seemed longer and more comprehensive than the US Constitution, enough to beat off the most formidable stateside contingency lawyer.

There is a reason for this. About six people have been lost since rafting began on the river. Only last autumn a Manchester woman drowned when she was sucked under after her raft capsized. The previous May a South African broke his neck on a rock.

The rapids must be treated with respect. One raft became stuck in what is known as the "seven day eddie", a swirl of water so powerful it is impossible to paddle out of it. It had to be dragged away after its occupants leaped to the bank. We watched them after clambering on to the rocky bank on the Zambia side of the river.

What was it like? Is there anything to be afraid of? Is it necessary to make your will beforehand? It was rather like riding on a roller-coaster, perched on the top of the seat, without a safety harness and without the certainty and direction afforded by rails.

There were no footholds on the rafts so the most useful prop was the paddle dug into the water.

The operators do not insist upon swimming ability - it wouldn't be much use - but they do expect some confidence in the water and everyone has to practise jumping in and climbing back on board before they begin.

Some level of fitness is also desirable, if only to negotiate the 750ft climb out of the gorge.

I was impressed by the standard of supervision but depressed by the foolhardiness of my younger companions who were at that age when they believe they are indestructible.

The water-flow, particularly after the rains, is usually sufficient to carry you well clear of rocks. But turbulent white water can be dangerous. It is that element of uncertainty that attracts people.

It was probably an acceptable risk, possibly less than cycling in London traffic. Definitely less, it seems, than that undertaken daily by the average suburban Australian. But then, we didn't fall out.

© Financial Times