Only by pure chance did Moses Onesmo Lyimo happen to be standing at the window of one of the buildings overlooking the channel leading into Dar es Salaam harbour at about one in the afternoon on 26 December 2004.

He recalls what looked like a sudden, violent ebb tide, then the water rolling back in again in a vast ripple - the tsunami - which swept the fishing boats parked on the beach below further into the harbour.

Finally the sea withdrew, leaving havoc behind it but only 13 known fatalities on the entire Tanzanian coast, three fishermen and ten people swimming on Cocoa Beach a short distance away.

Five boats were lost from Dar and 26 seriously damaged.

Lyimo, 62, doesn't remember exactly what was going through his mind, except that it wasn't "tsunami". "No one had ever seen such a thing in their lives," he says.

"We actually thought the world was ending."

Mobile phones

Looking down from the same vantage point five years later, he points out that few of the fishermen haggling over the price of a catch, fixing up their boats or just kicking over the sand would be likely to survive if a tsunami were to strike now.

Lyimo says none of the fishing boats have radios. "The only way they can communicate is with mobile phones, if they're inshore."

Tsunami early-warning in this part of the world has yet to be fully systemized, and it's a deficiency the "Ferry Marine" branch of the Tanzania Red Cross Society (TRCS), of which Lyimo is the disaster management officer, feels keenly.

Ferry Marine TRCS branch was set up as a direct result of the tsunami, to help fishermen understand the dangers and be better prepared.

It's also among the northern branches (Zanzibar is another) involved in a UN OCHA-funded programme being supported by the International Federation as part of the "Indian Ocean Tsunami Early Warning System Initiative".

Tsunami-preparedness on the Tanzanian coast also includes a similar programme here in the far south, supported by the French Red Cross in nine coastal villages and towns, and some German Red Cross-supported work.

The Red Cross effort countrywide involves communications, risk mapping, evacuation procedures, supplementary first-aid training and educational noticeboards.

"Now we know"

The Federation project includes two Wantok community radio sets - effectively broadcast stations in a suitcase - that will be installed in remote communities once granted frequencies and used for passing on early-warning information over a radius of some 25 kilometres.

Badly needed early-warning hardware has also been distributed in the form of cell phones, bicycles and megaphones.

To highlight the exceptional nature of the tsunami, Chimpele Hassan, 60, points out that his village of Msanga Mkuu, 40 kilometres north of the border, was founded some 300 years ago by a Mozambican known to local history only as "Malango".

"The tsunami," he says, "was 'number one'." The first. There'd been nothing to compare locally: only innocent mawimbis - before 2004 the standard Swahili term for a big wave.

People here were equally baffled by the behaviour of the sea on that day in December 2004, Hassan says - the sudden ebb followed by a surge which, mercifully, stopped just short of the houses closest to the beach.

Only a few boats were lost; there were no human casualties, even though people clustered on the beach to watch the extraordinary event.

"But now we know what to do," he adds, "Go to safer areas [using routes marked on the Red Cross risk map] and spread the word among our neighbours."

Whirlpools

In the nearby village of Msimbati, the testimony of Yusufu Ahmadi, 55, another experienced fishermen who has spent his whole adult life at sea, points up the vital importance of recognition in tsunami-preparedness work.

"People on the beach were surprised by the state of the ocean that day," he remembers. "They saw sudden dry areas [the ebb]. Then the water came again. Then it was normal.

"At one point it looked like whirpools."

Mohammed Shabani, 34, recalls that the water ebbed and surged four times. "We rushed to ask the elders what it was, but even they didn't know."

At Msimbati, where 15 boats were lost in 2004, it's probably true to say the tsunami was largely spent by the time it made landfall.

The villagers are well aware of the narrow escape they had, despite the material losses - and that they could be struck again.

Tsunami awareness, of course, extends to seamanship in these coastal communities where fishing is the only source of income.

Hassan says that before 2004, had he heard a tsunami alert while close inshore in his boat he would have raced in as fast as possible.

"Now," he says emphatically, "I would put to sea."