This is the spectacular moment a giant waterspout tornado formed on a lake between islands in Rwanda. The unusually long weather phenomenon extended from the clear blue water water to the dark clouds hovering above in Lake Ruhondo, Burera district on April 13. The whirlwind started in the water as a small rotating gust of wind before it slowly turned into a funnel-shaped column around 20 metres away from the houses. Teacher Schadrack Tuya who lives in the area was relaxing on his balcony when he saw the waterspout rapidly forming so he quickly warned his family members to be alert. Schadrack said: ‘I did not want to panic but I still alerted my family members about it just to be sure. I watched the waterspout grow from the small rotating wind it was until it become a giant that reached the sky.’ The waterspout grew bigger as it sucked in more water but fortunately stayed on the lake and did not move near the islands. It formed between islands where houses and other structures were built near the shore, which could have been easily damaged if it turned into a tornadic waterspout. After five minutes, the huge waterspout started to lose force before it completely dissipated after almost 15 minutes. Rwanda Meteorology Agency in Africa said in a statement that the waterspout was caused by shifting weather patterns in Burera district. The organisation said: ‘The weather phenomenon occurs when cold air moves across the lakes and results in large temperature differences between warm water and the overriding cold air.’ Waterspouts are tornadoes that form over water. They are intense columns of swirling clouds that stretch from the surface to the clouds above. They are most commonly found in subtropical areas and disappear shortly after they come into contact with land. Waterspouts are generally not dangerous but they can be a risk for aircraft flying through the area and for coral reefs and marine life in the water immediately below. Sailors should also try to avoid waterspouts – as the consequences of floating into one could be disastrous. The most common type of waterspout is a ‘fair weather waterspout’. They happen when winds merge from opposite directions near the water’s surface, creating a small area of spin. Sudden warm air at the surface, usually from a thunderstorm, causes the spinning air to rotate faster and it starts to rise – picking up water at the same time. Sometimes the air spins so fast that it stretches and a funnel appears from the water to the thunderstorm cloud above.