After becoming a tropical storm and attaining the name Haiyan at 00:00 UTC on November 4, the system began a period of rapid intensification that brought it to typhoon intensity by 18:00 UTC on November 5.
Despois de converterse nunha tormenta tropical e ser nomeado como Haiyan ás 00:00 UTC do 4 de novembro, o sistema comezou un período de rápida intensificación que o converteu nun tifón ás 18:00 UTC de 5 de novembro.