More rescues were underway Saturday morning in flood-ravaged West Virginia after a historic deluge killed at least 23 people there.

The floodwaters swept away cars, cut power to thousands and trapped hundreds in a shopping center after 10 inches of rain pounded parts of the state in just 24 hours.

Officials were still searching Saturday for some people missing in Greenbrier County, the area hardest hit by the floods with 15 deaths.

Elsewhere in the state, one person died in Ohio County, another died in Jackson County, and six died in Kanawha County, the West Virginia medical examiner's office said.

On Friday night, National Guard troops raced to build a temporary roadway in Kanawha County to rescue more than 500 people who had been stuck inside the Elkview Crossings Plaza since Thursday afternoon. Crews resumed evacuation efforts Saturday morning for those still inside.

"It's been a long 24 hours. The next 24 hours may not be much easier," Gov. Earl Ray Tomblin said Friday afternoon.

The rains, so heavy they were dubbed a "one-in-a-thousand-year event" by the National Weather Service, prompted officials to put 44 counties under a state of emergency, primarily in the southeastern part of West Virginia. Authorities rescued people off rooftops and whisked them out of their homes as water rose at an alarming speed.

The brutal floods took no mercy on their victims, killing people of all ages.

Among those found dead was 4-year-old Edward McMilllion, who went missing in Ravenswood, Jackson County, along the Ohio River, officials said. Local reports also said an 8-year-old in Ohio County fell into a creek and later died at a hospital.

Meanwhile, in Kanawha County, an elderly man was killed and a woman was swept away in her vehicle, reported NBC affiliate WSAZ.

More than 32,000 homes and businesses were still without power across the state Saturday morning, the West Virginia Division of Homeland Security tweeted. That number was down from a high of nearly 500,000 customers Thursday night.

In White Sulphur Springs in the southern part of the state, natural gas service was turned off after a burning home drifted down a swollen creek. It was captured on dramatic video.

Across the state, rivers reached historic highs Friday. In Clay County, northeast of Charleston, the Elk River rose to more than 33 feet, breaking the prior record of 32 feet set in 1888, officials said.

The downpour was the result of a "derecho" weather system that led to at leasteight confirmed tornadoes Wednesday in Ohio and northern Illinois on Wednesday evening and Thursday morning, according to the NWS.

Derechos are thunderstorms that produce widespread straight-line wind damage and happen most frequently in the late spring and summer, according

No flash flood warnings were issued for Saturday in West Virginia.