AUSTIN, Texas—Nearly 3.4 million utility customers around the United States were still without power Wednesday in the aftermath of a winter storm that overwhelmed power grids, and another blast of snow and ice threatened to impede the efforts to restore service. The latest storm front was expected to bring more hardship to parts of Texas, Arkansas and the Lower Mississippi Valley before moving to the Northeast on Thursday. “There’s really no letup to some of the misery people are feeling across that area,” said Bob Oravec, lead forecaster with the National Weather Service, referring to Texas. More than 100 million people live in areas covered by some type of winter weather warning, watch or advisory, the weather service said. More than two dozen people have died in the extreme weather this week, some while struggling to find warmth inside their homes. In the Houston area, one family succumbed to carbon …