Hurricane Hector remains a category four storm as it slowly moves west towards the south of Hawaii.
Hurricane Hector 2018-08-06. Photo: Wikimedia Commons
The eye of the storm, which had wind speeds as high as 217 km/h at its centre on Wednesday afternoon, is forecast to pass 300 kilometres to the south of the Big Island tomorrow.
The US National Weather Service said very large waves, gale-force winds and heavy rain could be expected in the state and residents should prepare.
The US Coast Guard has closed some ports to inbound traffic and all small boats are being told to seek sheltered waters.
Meanwhile, a bushfire on the Big Island doubled in size overnight and has burned through more than 600 hectares of Hawaii Volcanoes National Park.
The fire, which started at a ranch, remains uncontained and is now only a kilometre from a special ecological area.
It is being fanned by strong winds and very dry conditions.