Hundreds of Chinese tourists flee as tidal bore bursts through dam in annual event

hey came in their droves, all hoping to catch a glimpse of what is considered to be one of Mother Nature's more unusual spectacles.

However, these spectators unwittingly became part of the show when a huge tidal bore burst through a dam and spilled over the riverbank, sweeping scores of tourists off their feet.

One moment these bystanders stood transfixed at the banks of the Qiantang River in Haining, in east China's Zhejiang province, waiting to witness the natural phenomenon

Panic: Tourists flee as the ridal bore breaks through the dam by the Qiantang River in Haining, east China's Zhejiang province

Tidal wave: Spectators scatter as the water crashes over them in one of Mother Nature's more unusual phenomena

Swept away: Police try valiantly to protect the crowds from the tidal surge, including women and children, but the sheer weight and speed of the water carries off everyone in its path

The next they were running for their lives as a huge wave came crashing towards them, engulfing the crowds while others looked on helplessly.

While there were no fatalities, more than 20 people were injured after the wave swept through the throng, and some had to be be carried to receive medical attention.

Frenzy: The water engulfs the tourists, knocking some off their feet while others can only look on in horror

Wounded: The injured are carried away from the scene after the tidal bore crashed through a dam and swept through a crowd of spectators

Stretchered away: A woman is carried from the scene after the bore broke the banks of the river. More than 20 people were injured by the rogue wave, with many needing to be carried away for treatment

Despite the authorities warning onlookers to stand back from the river bank, many fail to heed the advice and end up trying to out-run the wave when it heads towards them.

Bores only occur in a few locations throughout the world, usually in areas with a large tidal range and where incoming tides are funnelled into a shallow, narrowing lake or river.

China's Qiantang River boasts the largest bore, up nine metres - or 30 feet high - and travelling up to 25mph.

Awesome power: Debris flies into the air after the water, which travels at speeds of up to 25mph, slams into the bank of the river. Many spectators are already beginning to panic