Aug 15 (Reuters) - Hurricane Lala approached Hawaii with

strong winds and heavy rain on Saturday, leaving more than

40,000 utility customers without power across the state as the

National Hurricane Center warned of "life-threatening"

conditions.

The poweroutage.com website showed 42,889 customers without

power as of 2:14 p.m. HST (0014 GMT on Sunday) in Hawaii,

including 31,792 on the Big Island and 7,203 in Maui County,

which includes the islands of Maui, Lanai and Molokai.

An advisory from the hurricane center at 2 p.m. HST

predicted 10 to 20 inches (25.4 to 51 cm) of rain on the Big

Island, and possibly up to 25 inches there, as well as 8 to 12

inches in eastern Maui and 4 to 6 inches in western Maui.

"This rainfall will produce life-threatening flooding and

mudslides, especially in areas of steep terrain," the center

said.

Hawaiian Electric warned customers to expect "possible

extended outages, potentially overnight," as the storm system

made its way westward across Hawaii. On the Hamakua Coast on the

Big Island, utility crews were assessing a 42-mile (67.6 km)

span of transmission lines after fallen trees knocked down

multiple poles and structures, Hawaiian Electric spokesperson

Darren Pai told TV station Hawaii News Now.

Earlier in the day, the U.S. National Hurricane Center said

Lala's maximum sustained winds reached 75 mph (120 km/h), making

it a Category 1 hurricane.

The Maunakea Weather Center, on the Big Island's tallest

peak, recorded wind gusts of more than 100 mph throughout the

early afternoon, although winds would have been slower closer to

sea level.

The Hawaii Department of Transportation said it was closing

Hilo International Airport and would close Ellison Onizuka Kona

International Airport at Keahole at 2 p.m. HST. The department

also closed the Hawaii Island, Maui County, and Kaua'i

commercial ports.