Hawaii is bracing for what could be its first direct hit from a hurricane since 1992, as category one storm Lala churns off its coast.

Packing 75mph (120km/h) winds, Lala gained hurricane strength on Saturday. In a worst-case scenario, it could dump up to 25in (63cm) of rain on Big Island and produce a 3ft storm surge.

A hurricane warning is in effect for Big Island, while Maui County, Oahu, Kauai and Niihau are under a tropical storm warnings. Officials have told residents to prepare for “life-threatening” conditions, including floods and mudslides.

The storm is expected to either make landfall or pass close to the southern tip of Big Island on Saturday, before continuing west.

The last time a hurricane made landfall on Hawaii’s Big Island was 155 years ago, according to the Associated Press news agency.

Over the weekend, Lala will continue moving westwards, and may weaken into a tropical storm, with the centre passing just below Hawaii’s other islands.