A terrifying waterspout whirls close to fishing boats in the Philippines. Footage shows the twister rotating off the coast of Masbate island in the Philippines on May 16, as dark storm clouds brewed overhead. Rain fell shortly after the waterspout appeared, residents said. Waterspout tornadoes form when wind merges from opposite directions near the water's surface, creating a small area of spin. Warm air at the surface causes the spinning air to rotate faster and it starts to rise – picking up water at the same time and forming the distinctive elephant-funnel shape. As warm air rises, the cooler air moves in below and then rises, too. Sometimes the air spins so fast that it stretches and a funnel appears from the water to the thunderstorm cloud above. 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 power of the wind can cause damage. They very rarely damage buildings as they dissipate when they reach land. However, they are dangerous of boats caught in their path or aircraft that fly through them.