 A long-running heat wave that's already shattered previous records across the country persisted Sunday, baking parts of the West with dangerous temperatures that caused the death of a motorcyclist in Death Valley and held the East in its hot and humid grip. An excessive heat warning, the National Weather Service's highest alert, was in effect for about 36 million people Sunday, about 10% of the population. Dozens of locations in the West and Pacific Northwest tied or broke previous heat records.