A typhoon is a violent storm that is formed over the Western Pacific. These storms are called a tropical cyclone. Typhoons are very similar to hurricanes. They begin near the equator, and move westward gaining in intensity and size. A storm surge often accompanies a typhoon. A storm surge is a giant wave that is caused by a storm. The winds near the center of a typhoon blow at very high speeds. They often reach 150 miles per hour. A typhoon can be up to 300 miles wide.