Lonesome ranger

Of the four stations, two, including Wu's, are not connected to the electricity grid, and rely on photovoltaic power generation. Stored energy, however, is not always enough and the stations sometimes experience cold temperatures during periods without sunlight.

Despite such hardships, nothing compares to the profound loneliness of life on the reserve — a desolate place where the whispering of the wind is endless. That companionship of fellow rangers is appreciated and crucial to maintaining mental equilibrium in the harsh environment.

Lu Shengrong, 42, found camaraderie in Tian Shoujun, who is 11 years his senior and began working at Tuliangdao Station in 2017. "I had been a driver before I came here. The truck for our field surveys was no problem until it got stuck in the sand. Then you had to get it out yourself," Tian said with a laugh.

"But there were new things to learn, like filling out field reports and cooking, which I never had to do before when I lived with my family. Here, we take turns cooking."

As he speaks, he confidently stretches strands of hand-pulled noodles, a local specialty. The tiny kitchen where Tian honed his culinary skills — like most indoor spaces at Tuliangdao Station — was carved directly out of the rugged Yardang formations. "We have four cave dwellings. Each one is about 45 sq m and takes around a month and a half to complete," he said.

The landforms, which were once part of the seafloor, are distinctly stratified with layers of hard and soft sedimentary rock.

"The harder layers, like sandstone and limestone, are especially tough to drill through," explained Lu.

"Builders bore at an angle from top to bottom, pour water down the shaft to soften the rock overnight, and resume drilling the next day, sometimes with the help of explosives."

Even a pet dog is given his own Yardang cave — a cool, shaded burrow for escaping the relentless sun.

The caves typically have no windows, as they have no need of wind, and are lit by electric lights from morning to night. Only when the door opens does a sliver of the outside world slip in, with light flooding the dwelling like water through a crack in a stone.