ROCHESTER, N.Y. - A storm blamed for at least 41 deaths in six states spread into the Northeast yesterday, coating trees, power lines and roads with a shell of ice up to a half-inch thick and knocking out power to more than half a million homes and businesses.

Ice-covered roads cut into Martin Luther King's Birthday observances from Albany, N.Y., to Fort Worth and Austin, Texas, where officials also canceled Gov. Rick Perry's inauguration parade today because another round of ice was expected during the night.

The weight of the ice snapped tree limbs and took down power lines, knocking out electricity to about 145,000 customers in New York state and New Hampshire.

Even in Maine, a state accustomed to winter weather, a layer of sleet and snow on roads shut down businesses, day-care centers and schools.

In hard-hit Missouri, the utility company Ameren said it probably would not have everyone's lights back on until tomorrow night. Overnight temperatures were expected to drop into the single digits. As of yesterday afternoon, about 312,000 homes and businesses still had no electricity.

Missouri National Guardsmen went door to door, checking on residents, and helped clear slick roads.

About 100,000 homes and businesses that had been blacked out in Oklahoma, some since the storm's first wave struck Friday, also were waiting for power. Ice built up by sleet and freezing rain was 4 inches thick in places. Oklahoma officials strongly discouraged travel, saying the frigid weather would refreeze slush and water on roads.

About 127,000 customers were without electricity yesterday in Michigan.

More than 160 flights were canceled at Dallas-Fort Worth International Airport.

Waves of freezing rain, sleet and snow since Friday had been blamed for at least 15 deaths in Oklahoma, eight in Missouri, eight in Iowa, four in New York, three in Texas and one in Maine. Seven of the Oklahoma deaths occurred when a minivan carrying 12 people slid off an icy highway Sunday and hit an oncoming truck.