VOV.VN - Typhoon Wipha, packing powerful winds and torrential rains, is expected to move into the Gulf of Tonkin on July 21, and strike the northern coastal provinces of Vietnam within the coming hours,

Storm Wipha threatens the region with intense rainfall exceeding 600mm and raises the risk of flash floods and landslides.

Satellite imagery can help determine the strength, size and cohesion of a storm. The stronger a storm becomes, the more likely an eye will form in the center. When the eye looks symmetrical, that often means the storm is not encountering anything to weaken it.