Ilya and I immediately suited and set to work lowering the mobile lab and shooting anchors deep into the soil and rock beneath. We slung cables over the lab from anchor to anchor, then pulled folded plastic foils from the boot in the lab’s round stern, stretching them from the ground and fastening them to the lab’s sides to make a wind ramp. The foil stiffened quickly into the proper shape. It would also function as a shield against debris.

“We’ve got about ten minutes,” I said. We both looked into the arroyo at the slab-sided shed with its precious specimens, a tin shanty that would love to fly.

“There’s a spare tarp and foil,” Ilya said. “We can rig it in six minutes — or we can get inside.”

“Rig it,” I said. He grabbed my hand and squeezed it.

We worked quickly. Surges could be terribly destructive even to a buried station if it was unprepared. The center of a surge’s curl could compress to as much as half a bar, a rolling-pin of tight-packed air moving at well over eight hundred kiphs; and the farther a surge rolled, the tighter it packed, until it blew itself out against a volcano or plateau and spread dust and cyclones over half of Mars.

We stiffened the shed’s foil and kicked the tarp pegs. All was firm. We ran for the lab and sealed the flap behind us. A little excavator clambered up from a fresh-dug trench under the lab’s cylindrical body and fastened itself to its receptacle in the bottom of the lab. We crawled into the trench and spread our personnel foils. The foils undulated, stiffened, and glued themselves to the edges of the trench.

Ilya switched on a torch and shined it in our faces. We lay in the coffin-shaped ditch, with two layers of foil and the ponderous mobile lab over our heads, hands tight-clenched.

Outside: a horrid empty silence. Even the rock was quiet; the surge was still dozens of kilometers away. Ilya removed his slate from his utility belt and instructed the mobile lab’s roof camera to show us what was happening. To the northwest, all was dark gray shot through with streaks of brown.

“Are we cozy?” he asked. Our helmet radios whined faintly, we lay so close together.

“Snug as bunnies in a pot,” I said, teeth clenched.

“I’m sorry I got you into this, Casseia…”

I couldn’t clamp my hand over his mouth, but I made the gesture against his helmet anyway. “Shh,” I said. “Tell me a story.”

Ilya excelled at making up fairy tales on the spur of the moment. “Now?” he asked.

“Please.”

“Long ago,” he began, voice husky, “and long after now, two rabbits dug a hole in the farmer’s garden and ate through all of his water lines…”

I closed my eyes, listening.

Our helmets pressed against the rocks and each other. Before Ilya had finished the story, I laid my hand against the bottom of the ditch, palm flat to pick up vibrations. The line of dust and compressed atmosphere to the west stretched inky-black and very close. It began to obscure the horizon. Only seconds now…

All around, through the rocks, we heard a low grumbling, then a distinct, rhythmic pounding. “There it is,” I said. “Plains buffalo.” We had all seen Terrie Westerns.

Ilya placed his hand over mine. “Freight trains,” he said. “Hundreds of them.”

I began to shiver. “Have you been through one of these?” I asked.

“When I was a kid,” he said. “In a station.”

“Anybody hurt?”

He shook his head. “Small one. Only a quarter of a bar. Made a lot of noise when it went over.”

“What does it sound like when it goes over?”

He was about to tell me when I heard for myself. The sound started out ghostly — the sibilant patient whine of a strong Martian wind, audible through our helmets even in the trench, backed by the staccato of pebbles and dust striking against the foils and tarps. The blackness seemed to leap over the land.

I felt pressure in my ears, thin fingers pushing into my head. I opened my eyes to slits — my eyelids had pressed themselves tight shut instinctively — to see Ilya. He lay on his back, shoulder wedged against the side of the trench, staring up, eyes searching.

“This is going to be a bad one,” he said. “I’ll finish the story later, okay?”

“Okay. But don’t forget.” I shut my eyes again.

For a moment, the surge sounded like huge drums. A thin shriek descended into a monstrous, horrifying bellow. I thought of a ravening god marching over the land, Mars itself, god of war, furious and implacable, searching for things that might be frightened, things that might die.

The pressure suit loosened around me, then clung tight to my skin. A sharp pain in my ears made me screw up my face and groan. The torch fell between us. Ilya grabbed it again, shined it on his face, shook his head, face slick with tears, and held me tightly. I could feel his heart through the suits.

The vibration of the trench walls stopped. We lay for a moment, waiting for it to begin again. I started to get up, pushing against the tarp, frantic to see daylight — but Ilya grabbed my shoulder and pressed me down. I could not hear very well. The torch illuminated his face; he was trying to mouth words to me. Somehow I understood through my fear — rocks and dust would be falling outside. We might be killed by rocks falling from thousands of meters in the wake of the surge, striking at eighty or ninety meters per second. I pressed myself against him, mind racing, grimacing at the pain.

Time passed very slowly. My fear turned to numbness, and the numbness faded into relief. We were not going to die. The worst of the surge had passed over and we were still in the trench — but a new fear hit me, and I had to fight myself to keep from clawing out of Ilya’s embrace. We could be buried under a fresh dune — tons of dust and sand, dozens of meters high. We would never dig out. Our oxygen would be depleted and we would suffocate, this trench would become just what it seemed, a grave… I began to squirm, breath harsh and short, and Ilya struggled to keep his arms around me. “Let me go!” I shouted.

Suddenly, I flinched and stopped thrashing. A light had hit me in the face, not our torch. The lab’s arbeiters were ripping away the foils and tarps, searching for us.

The chief arbeiter appeared on the edge of our trench. A jointed arm had been wrenched loose and the machine was covered with dents and red smears — rock impacts. It had weathered the storm outside, tending the edges of the foil until the last moment. It must have been blown around like a small can.

Ilya pulled me up out of the ditch in deathly silence. The mobile lab was still intact above us; we might be able to get to a station on our own.

We brushed each other down, more for the reassurance of physical contact than any other reason. I felt light-headed, giddy with still being alive. We walked beneath the main foil and tarps, inspecting the lab, then emerged to stand in the open.

The foil on the specimen shed had failed. It was nowhere to be seen.

The sky from horizon to horizon glowered charcoal-gray, almost black. Dust fell in thick snaking curtains, great sheets unrolling, drifting, hiding. We gathered the arbeiters beneath the lab and climbed the steps into the airlock, quickly sucking the gray dust from our suits, then stripped.

Ilya insisted I lie on the narrow fold-down cot. He lay on his cot across from me, then got up and pushed in close beside me. We shivered like frightened children.

We slept for an hour. When we awoke, I felt ecstatic as if from drinking far too much high-powered tea. Everything seemed sharply defined and highly colored. Even the dust in the lab interior smelled sweet and essential. The pain in my ears had subsided to a dull throb. I could still hear, but just barely.

Ilya showed me the lab’s weather record. The surge had topped at two bars.

“That’s impossible,” I said.