Hawaii on Wednesday braced for a walloping by a rare duo of storms headed for the holiday paradise, with local residents rushing to stock up on water and flashlights.
Hurricane Iselle, while predicted to weaken to a tropical storm, was expected to bring strong wind, heavy rains and possibly damaging swells to the archipelago's main islands by Thursday.
"Tropical storm conditions are possible on the Big Island of Hawaii on Thursday and portions of Maui County Thursday night," the Central Pacific Hurricane Center (CPHC) warned.
Rains associated with Iselle are expected to affect the entire state by late Thursday and Friday and "could cause life-threatening flash floods and mud slides."
A tropical storm watch was in effect for Hawaii and Maui counties, the CPHC said, adding that "watches will likely be required for additional islands later today."
At 1200 GMT, Iselle was about 745 miles (1,200 kilometers) east of Hilo, Hawaii, and some 945 miles east-southeast of Honolulu.
While currently packing maximum sustained winds near 90 miles per hour (145 kilometers per hour), forecasters predicted the system would be downgraded to a tropical storm by Thursday.
Swirling on Iselle's heels in the eastern Pacific is Hurricane Julio.
With maximum sustained winds of nearly 75 miles per hour, at 0900 GMT it was 1,750 miles east of Hilo and advancing  west-northwest.
"Some strengthening is forecast during the next day or so," the National Hurricane Center said.
As the two storms approached, authorities urged Hawaii residents and tourists alike to prepare, sparking long lines at stores as people snapped up basics such as water, flashlights and batteries.