Hurricane Lane has strengthened to a Category 5 storm as it heads toward Hawaii where residents are bracing for "life threatening" winds and flooding when it hits the US islands this week.
The hurricane, packing 260km/h winds was expected to hit Hawaii's Big Island on Thursday with gusts capable of damaging roofs and knocking out power, the National Hurricane Centre (NHC) warned.
"Preparations to protect life and property should be rushed to completion," the centre said.
The centre of the storm is expected to track "dangerously" close to or over the islands Thursday through Saturday, the NHC said.
"Slow weakening is forecast during the next 48 hours, but Lane is forecast to remain a dangerous hurricane as it draws closer to the Hawaiian Islands," the centre said.
After hitting the Big Island, the storm is expected to churn north over the islands of Maui, Lanai and Moloka'i, which were all under hurricane and flash flood watches.

This NASA satellite imagery shows Hurricane Lane in the Central Pacific Ocean southeast of the Hawaiian Islands at 2:01 p.m. HST (21:01 GMT) Source: AAP
Rainfall of 51cm in some areas could lead to major flash flooding, landslides and mudslides, the NHC said.
Devastation caused by winds and flooding may make locations uninhabitable for weeks and authorities warned Hawaii residents to be prepared to evacuate their homes.

Bryce and Dom Boeder of Waimea, Kauai, load their truck with storm supplies. Source: AAP
The Big Island is still reeling from a three-month eruption of Kilauea volcano, which forced thousands of residents to evacuate their homes and engulfed hundreds of structures in lava.