 Hurricane Dot of August 1959 was at its time the costliest tropical cyclone in Hawaiian history . Dot was first identified as a strong tropical storm southeast of Hawaiʻi on August 1 . The storm was potentially a continuation of a previously unnamed tropical cyclone that was monitored west of the Baja California Peninsula from July 24 @-@ 27 , but was never confirmed as a tropical cyclone . On August 2 , Dot was upgraded to a hurricane , and on the 4th it was upgraded to a major hurricane . The hurricane intensified into a Category 4 hurricane on the Saffir-Simpson Hurricane