He walked again, fortunately almost downwind. After five or six painful minutes his wrist beeped.

Aonia said, “You’re right on course!”

This was encouraging, and he carried on with a bit more speed, though the wind was penetrating through his ribs right to his core.

“Okay, Sax! Sax?”

“Yes!”

“You and your car are right on the same spot!”

But there was no car in view.

His heart thudded in his chest. Visibility was still some twenty meters; but no car. He had to get shelter fast. “Walk in an ever-increasing spiral from where you are,” the little voice on the wrist was suggesting. A good idea in theory, but he couldn’t bear to execute it; he couldn’t face the wind. He stared dully at his black plastic wristpad console. No more help to be had there.

For a moment he could make out snowbanks, off to his left. He shuffled over to investigate, and found that the snow rested in the lee of a shoulder-high escarpment, a feature he did not remember seeing before, but there were some radial breaks in the rock caused by the Tharsis rise, and this must be one of them, protecting a snowbank. Snow was a tremendous insulator. Though it had little intrinsic appeal as shelter. But Sax knew mountaineers often dug into it to survive nights out. It got one out of the wind.

He stepped to the bottom of the snowbank, and kicked it with one numb foot. It felt like kicking rock. Digging a snow cave seemed out of the question. But the effort itself would warm him a bit. And it was less windy at the foot of the bank. So he kicked and kicked, and found that underneath a thick cake of windslab there was the usual powder. A snow cave might be possible after all. He dug away at it.

“Sax, Sax!” cried the voice from his wrist. “What are you doing!”

“Making a snow cave,” he said. “A bivouac.”

“Oh Sax— we’re flying in help! We’ll be able to get in next morning no matter what, so hang on! We’ll keep talking to you!”

“Fine.”

He kicked and dug. On his knees he scooped out hard granular snow, tossing it into the swirling flakes flying over him. It was hard to move, hard to think. He bitterly regretted walking so far from the rover, then getting so absorbed in the landscape around that ice pond. It was a shame to get killed when things were getting so interesting. Free but dead. There was a little hollow in the snow now, through an oblong hole in the windslab. Wearily he sat down and wedged himself back into the space, lying on his side and pushing back with his boots. The snow felt solid against the back of his suit, and warmer than the ferocious wind. He welcomed the shivering in his torso, felt a vague fear when it ceased. Being too cold to shiver was a bad sign.