 On October 3 a tropical depression developed about 500 miles (800 km) south-southeast of Guam, likely having originated from a tropical disturbance in the eastern Caroline Islands.The system gradually strengthened to typhoon status while it tracked west-northwestward.On October 7 the typhoon turned to the northwest and moved through the southern Luzon Strait, passing about 30 miles (48 km) southwest of Basco in the Batanes on October 9.