The National Weather Service in Honolulu has issued a flash flood warning through midnight for areas of North Kohala and South Kohala.
At 8:45 p.m., radar showed "torrential" rain over parts of the leeward slopes of Kohala Mountain, according the service. The heaviest rain is currently over leeward slopes between Mahukona and Kawaihae.
The service specifically noted Kohala Mountain Road and Akoni Pule Highway in the warning issued shortly before 9 p.m. Saturday.
Residents are advised to stay away from streams, drainage ditches and low-lying areas.
Motorists are advised to use caution while driving because rainfall and runoff can cause hazardous driving conditions like reduced visibility and poor braking action.