Hurricane Lala strengthened into a Category 1 storm Saturday as it bore down on Hawaii’s Big Island, bringing heavy rain, damaging winds and the threat of dangerous flooding.

The U.S. National Hurricane Center said Lala strengthened into a hurricane with maximum sustained winds of around 75 mph, or 120 kilometers per hour, as it approached the island.

A hurricane warning was in effect for the Big Island, while tropical storm warnings covered other parts of the Hawaiian chain.

Lala slowed and turned northwest as it began interacting with the Big Island, with forecasters warning that heavy rainfall and gusty winds would continue affecting the island.

Authorities warned of potentially life-threatening flash floods and landslides, particularly in mountainous areas. Rainfall totals could reach as much as 25 inches, or about 635 millimeters, in some elevated areas.

Hawaii Gov. Josh Green urged residents to shelter in place as conditions deteriorated, while emergency shelters were opened and residents stocked up on food, water and other supplies.

The storm also disrupted transportation across the state. Authorities moved to close Hilo International Airport and Ellison Onizuka Kona International Airport on the Big Island, while commercial ports in Hawaii Island, Maui County and Kauai were also closed as a precaution.

Strong winds were already being recorded Saturday, with observations near South Point showing sustained winds of 41 mph and gusts reaching 64 mph.

Forecasters warned residents that Lala's hazards extended beyond the storm's center, with dangerous surf, strong winds and torrential rainfall capable of causing damage even in areas that do not experience a direct hit.

The National Hurricane Center continued to issue advisories on Lala as the hurricane moved through the Hawaiian Islands.