MURRAY, Ky. — Utility crews renewed work in subfreezing temperatures today to put the electricity back on for nearly a million customers left in the dark by an ice storm that crippled parts of several states this week.

Thousands of people in ice-caked Kentucky awoke in motels and shelters, asked to leave their homes by authorities who said emergency teams in some areas were too strapped to reach everyone in need of food, water and warmth.

A 20-degree temperature boost was forecast across much of the region.

Dozens of deaths have been reported and many people are pleading for a faster response to the power outages. About 536,000 homes and businesses across Kentucky were without power, down from more than 600,000, the largest outage in state history.

From Missouri to Ohio, thousands were waiting in shelters for the power to return. Others were trying to tough it out at home.

In Poplar Bluff, Mo., a man used a barbecue grill inside to cook and keep warm, deputy police chief Jeff Rolland said.

"Luckily, one of our volunteers was in a position to see what he was doing and inform him of the carbon monoxide dangers of using a charcoal grill inside a residence," Rolland said.

The storm that began in the Midwest had been blamed or suspected in at least 42 deaths, including 11 in Kentucky, nine in Arkansas, six each in Texas and Missouri, three in Virginia, two each in Oklahoma, Indiana and West Virginia and one in Ohio.