Hawaii suffered its worst flooding in more than 20 years as heavy rains fell on soil already saturated by downpours from a winter storm a week ago, officials said on Friday, while warning that more rain was expected during the weekend.

Muddy floodwaters smothered vast stretches of Oahu’s North Shore, a community world renowned for its big-wave surfing.

Raging waters lifted homes and cars and prompted evacuation orders for 5,500 people north of Honolulu.

Authorities cautioned that a 120-year-old dam could fail.

Governor Josh Green said the cost of the storm could top US$1 billion, including damage to airports, schools, roads, people’s homes and a Maui hospital in Kula.

An aerial view of homes surrounded by floodwater in Waialua, Hawaii, on Friday. Photo: APAn aerial view of homes surrounded by floodwater in Waialua, Hawaii, on Friday. Photo: AP

“This is going to have a very serious consequence for us as a state,” Green said at a press conference.