Storm expected to strengthen to hurricane as state of emergency declared amid danger of ‘life-threatening’ floods

Tropical Storm Lala is set to hit Hawaii’s Big Island with hurricane force in a matter of hours, bringing dangerous winds, heavy rainfall and high surf in a sign of what a strengthening “super” El Niño in the Pacific may bring.

The tropical storm is currently about 420 miles (675km) south-east of Hilo on the archipelago’s largest island, the National Oceanic and Atmospheric Administration (Noaa) said in its latest advisory, packing winds of 60mph (97km/h). Lala is forecast to strengthen into a hurricane as it approaches the Big Island.