During a rainstorm that partially obscured the light of a a nearly full moon, 97 runners pushed off in desolate Death Valley with the launch of a 48-hour annual ultramarathon billed as the world´s toughest foot race – the Badwater 135. After starting late Monday night, the men and women ranging in age from 19 to 69 and hailing from 21 countries and 26 U.S. states, are running amid an excessive heat warning. With daytime temperatures as high as 120 degrees Fahrenheit (48.8 Celsius) and night heat above 100 F (37.7 C), they are traveling over roadways open to traffic and passing through places with names like Furnace Creek, Devil’s Golf Course and Devil’s Cornfield. “For me it’s all about seeing what I can do, you know, testing my own limits, seeing how well I can do these extreme things,” said 46-year-old runner Jessica Jones from Dauphin Island, Alabama, who was running her second Badwater 135, which starts in the valley’s Badwater basin. Luke Thomas, 44, from San Diego, was running his fourth 135-mile (217-kilometer) ultramarathon this calendar year. Thomas didn’t know if the humidity from the late Monday storm would make the first part of the race harder or easier. While running an ultramarathon race in Brazil in January “the humidity almost killed me,” he said. The race, which started in 1987, always takes place in mid-July, when temperatures peak in Death Valley National Park. The park has seen record-setting temperatures this month, including nine straight days of 125 F (51.6 C) or above. It’s so dangerous that a motorcyclist traveling in the park died from heat-related illness on July 6, and several more in his group fell ill. A woman with heat illness was rescued in the park on Thursday after she and a man got lost on a hike in an area called Badlands Loop as temperatures hit around 110 F (43.3 C) at 9:30 a.m. No runner has died during the race, but a few people have landed in the hospital, said race director Chris Kostman, of AdventureCORPS, which organizes the race. The route actually dates back to a decade earlier when it was successfully completed by a solo runner, he said. Participants start at the lowest point in North America at 282 feet (86 meters) below sea level. The finish line is 8,300 feet (2,530 meters) high at the Whitney Portal, the trailhead to California’s Mount Whitney, the highest point in the contiguous U.S. Unlike more traditional marathons in which runners race close together, participants in the Badwater 135 are well spaced out on the road. The race is invitation only and limited to 100 runners who have run ultramarathons of at least 100 miles (160 kilometers) or longer over the span of three years. Only one-third of the runners each year can be repeat participants to allow others a chance. When this year’s runners set out late Monday, temperatures were around 108 F (42.2 C). Their northbound path was illuminated by headlamps and the slightly obscured moonlight.