The City of Houston has begun emerging from the grips of an unprecedented winter storm. Houston Mayor Sylvester Turner said Thursday that electricity had been restored to many residents who had gone without it, in some cases for a day or more, with the city having endured rolling outages since early Monday. He also said the pressure in the city's main water system had improved since Wednesday, although Houston residents remain under a boil water notice. "Things are improving, but we still have a ways to go," Turner said. Turner said the boil water notice, under which residents are advised to boil tap water for at least two minutes before using it for consumption or cooking, could remain in effect through the weekend.