A motorcyclist died and another was hospitalized after they became overwhelmed by heat amid record-breaking temperatures in Death Valley National Park over the weekend, authorities said.

The incident took place on Saturday in the Badwater Basin portion of the park as the temperature soared to 128 degrees, marking a daily record, Death Valley National Park representatives said.

A group of six motorcyclists were making their way through the area when two of them suffered significant heat-related illness, park representatives said in a written statement.

One of the riders died due to heat-related illness, officials said. A second was taken to a hospital for treatment of “severe heat illness.”

Four other members of the group were treated at the scene, authorities added.

The record-setting heat prevented rescuers from using a helicopter to transport the victims, as they can’t safely fly in temperatures above 120 degrees, according to park officials.

Saturday’s high temperature broke the area’s previous daily record of 127 degrees, set in 2007.

Park Superintendent Mike Reynolds urged visitors to be vigilant of the serious threat posed by extreme heat.

“High heat like this can pose real threats to your health,” he said. “While this is a very exciting time to experience potential world record setting temperatures in Death Valley, we encourage visitors to choose their activities carefully, avoiding prolonged periods of time outside of an air-conditioned vehicle or building when temperatures are this high.”

When the head index exceeds 99 degrees, ambient air, such as the wind experienced by motorcyclists, is no longer able to provide relief from the heat, officials said.

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“Heat illness and injury are cumulative and can build over the course of a day or days,” according to the statement. “Besides not being able to cool down while riding due to high ambient air temperatures, experiencing Death Valley by motorcycle when it is this hot is further challenged by the necessary heavy safety gear worn to reduce injuries during an accident.”

Hiking and other outdoor activities are not recommended during periods of extreme heat, especially at lower elevations, park officials said.

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Authorities also urged additional safety measures:

  • Stay hydrated
  • Wear loose-fitting clothing, a hat and sunscreen
  • Avoid the sun during the peak of the day
  • Carry an umbrella