A long-running heat wave that has already shattered previous records across the U.S. persisted on 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, or about 10% of the population, said NWS meteorologist Bryan Jackson. Dozens of locations in the West and Pacific Northwest tied or broke previous heat records. Many areas in Northern California surpassed 110 degrees (43.3 C), with the city of Redding topping out at a record 119 (48.3 C). Phoenix set a new daily record Sunday for the warmest low temperature: it never got below 92 F (33.3 C). A high temperature of 128 F (53.3 C) was recorded Saturday and Sunday at Death Valley National Park in eastern California, where a visitor died Saturday from heat exposure and another person was hospitalized, officials said. The two visitors were part of a group of six motorcyclists riding through the Badwater Basin area amid scorching weather, the park said in a statement. The person who died was not identified. The other motorcyclist was transported to a Las Vegas hospital for “severe heat illness,” the statement said. Due to the high temperatures, emergency medical helicopters were unable to respond, as the aircraft cannot generally fly safely over 120 F (48.8 C), officials said. Read more: https://www.9news.com/article/news/nation-world/heat-wave-in-the-us-shatters-records/507-ab1a4003-618b-42c5-961d-a39bef72e05e More local videos here: https://youtube.com/@9news Subscribe to NEXT: https://youtube.com/@Nexton9NEWS Stay connected: 9NEWS Website: https://www.9news.com/ Facebook: https://www.facebook.com/ilike9news Twitter: https://twitter.com/9NEWS Instagram: https://www.instagram.com/9newsdenver/ Download the 9NEWS App: https://www.9news.com/appredirect/ Sign up for the 9NEWSLETTER: https://www.9news.com/email 9NEWS (KUSA) is located in Denver, Colorado.