Hawaii has 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 say more rain is expected over the weekend. Muddy floodwaters have smothered vast stretches of Oahu’s North Shore, a community world-renowned for its big-wave surfing. Raging waters have lifted homes and cars and prompted evacuation orders for 5,500 people north of Honolulu. Authorities caution a 120-year-old dam could fail. Gov. Josh Green says the cost of the storm could top $1 billion, including damage to airports, schools, roads, people’s homes and a Maui hospital in Kula.