BENTOTA, Sri Lanka - It was a random mobile phone alert that told my family, huddled, baffled, in a rocking fishing boat off the coast of Sri Lanka, that the tsunami was on its way.

The tiny vessel being buffeted by enormous waves had left port in tranquil, sunny weather just hours earlier as part of a routine tourist excursion. Amid the cloudless blue skies and calm waters of Bentota, a beautiful stretch of coast between Colombo and Galle, there was no indication of the string of huge waves that were rolling across the ocean, and the devastation that they were about to inflict.

My father, boyfriend and the partners of two of my sisters had set out on a deep sea fishing trip from a nearby harbour before sunrise. Armed with bottles of water, sun cream and vodka they had left from a nearby harbour nestled in an ancient glass fibre boat equipped with three decrepit life jackets.

Sitting on my sunny hotel balcony at the Taj Exotica, situated above the beach, all appeared to be normal. Local children were playing makeshift cricket on the beach and an elephant ambled along the shore offering rides.

Shortly after 9am I watched the first giant wave creep forward, swiftly and relentlessly. Immediately it swept over and past the beach. Within 20 minutes the water had drained, leaving behind a trail of devastation in the form of wrecked boats, splintered furniture and doors.

There was an odd absence of people. This, it transpired, was the only the first in a series of such waves that would batter the coastline.

Meanwhile, with conditions evidently deteriorating at sea, my father had glanced at his mobile phone - it contained an Orange news alert warning of catastrophic weather in the region. The sea swelled dramatically as the skipper tried - and failed - to bring the 20 foot boat into the harbour. Forced back out to the open sea, the boat was buffeted by the wreckage of other vessels. Eventually, against mountainous seas their boat struggled into the port.

At the hotel we received a short, but hugely welcome text message from my dad. It read simply "yes".

As we gathered anxiously around the swimming pool area of the hotel, located safely on the fourth floor, the immediate traumas of those around us began to emerge.

Jaime Jones, a 25-year-old lawyer from London, described how she was swimming in the sea with her mother when the tidal wave struck. The pair were swept into the gardens of the hotel where they became trapped waist-high in water in one of the ground floor rooms.

"It happened so quickly," she said. "It had seemed like the perfect day but the water rushed in so fast. We were extremely lucky as two members of staff were able to rescue us."

Her father Bob Jones, 55, a company director from Plymouth who dislocated his knee in an attempt to find his family, added: "It was terrifying. It was just such a relief to find them. I hope that other people on the beach are as lucky."