An arctic blast that gripped much of the United States on Saturday left more than 700,000 without power, at least 16 dead from weather-related car crashes and thousands stranded due to flight cancellations.

Plummeting temperatures were expected to bring the coldest Christmas Eve on record, and energy systems across the country were strained by rising demand for heat and storm-related damage to transmission lines.

The latest outage numbers are a sharp drop from the 1.8 million US homes and businesses left without power as of early Saturday morning, according to tracking site Poweroutage.us.

Many electric companies continued to ask customers to conserve energy by not running large appliances and turning off unneeded lights.

Duke Energy by late Saturday afternoon told customers it had ended the 15-30-minute rolling blackouts across North and South Carolina that it had initiated earlier in the day until additional electricity was available.

Disruptions upended daily routines and holiday plans for millions of Americans during one of the year's busiest travel periods.