A major winter storm that already cut electric power to about 350,000 homes and businesses from Texas to the Ohio Valley was set to leave Pennsylvania and New England glazed in ice and smothered in snow. A National Weather Service meteorologist said a foot of snow was expected to accumulate Friday in northern New York and northern New England. But it was the ice that threatened to wreak havoc on travel and electric service in the Northeast before the storm heads out to sea late Friday and Saturday.