AUSTIN, Texas—Power outages in Texas dropped below 1 million on Thursday morning for the first time in four days, but many people remained without electricity or safe drinking water after winter storms wreaked havoc on the state’s power grid and utilities. Meanwhile, heavy snow and ice were expected Thursday in the Appalachians, northern Maryland, and southern Pennsylvania, with the wintry weather moving into the Northeast by nightfall. This week’s extreme weather has been blamed for the deaths of more than 30 people, some of whom perished while struggling to keep warm inside their homes. In the Houston area, one family succumbed to carbon monoxide from car exhaust in their garage. A grandmother and three children died when flames escaped the fireplace they were using to keep warm. In Texas, more than 600,000 homes and businesses were still without electricity Thursday morning, down from about 3 million the day before. But Texas’s grid …