Severe rains have caused significant flooding in Hawaii.
More than 4,000 residents have been ordered to evacuate.
Officials are concerned about the potential failure of a 120-year-old dam.
Briefing: Over 4,000 told to evacuate flooding in Hawaii as officials warn 120-year-old dam could fail
Strategic angle: Muddy floodwaters from severe rains have inundated streets, prompting evacuation orders for over 4,000 residents in Hawaii.