 Initially noted as a tropical disturbance in the Philippine Sea on October 2 , the system moved slowly west @-@ northwest to the south of the subtropical ridge , becoming a tropical depression on October 4 . Crossing the Philippines , the depression caused heavy rainfall and flooding as it emerged into the South China sea and developed into a tropical storm on October 9 . Development was slow due to strong upper level winds from the northeast displacing thunderstorms west @-@ southwest of its center . Continuing to track north of due west , Dom made landfall in Vietnam and dissipated as it moved along the Laos / Vietnam border on October 12 . A total of 16 perished and damage totalled US $ 4 million ( 1986 dollars ) in Luzon . 
