AUSTIN, Texas—Power was restored to more homes and businesses Thursday in states hit by a deadly blast of winter that overwhelmed the electrical grid and left millions shivering in the cold this week. But the crisis was far from over in parts of the South, where many people still lacked safe drinking water. In Texas on Thursday, about 325,000 homes and businesses remained without power, down from about 3 million a day earlier, though utility officials said limited rolling blackouts were still possible. The storms also left more than 320,000 homes and businesses without power in Louisiana, Mississippi and Alabama. About 70,000 power outages persisted after an ice storm in eastern Kentucky, while nearly 67,000 were without electricity in West Virginia. And more than 100,000 customers remained without power Thursday in Oregon, a week after a massive snow and ice storm. Maria Pope, the CEO of Portland General Electric, said …