But this time the light of day browned and dimmed until it might as well have been night— a chocolate night, howling over the boulder and rattling the outer window. “The winds have gotten so strong,” Sax remarked pensively. Then the howl lessened, while it was still dark out. Nirgal felt more and more sick the less the wind howled— until the air was still, and he was so nauseated he could scarcely stand at the window. Global dust storms sometimes did this; they ended abruptly when the wind ran into a counterwind, or a particular landform. And then the storm dropped its load of dust and fines. It was raining dust now, in fact, the boulder’s windows a dirty gray. As if ash were settling over the world. In the old days, Sax was muttering uneasily, even the biggest dust storms would only have dropped a few millimeters of fines at the end of their runs. But with the atmosphere so much thicker, and the winds so much more powerful, great quantities of dust and sand were thrown aloft; and if they came down all at once, as sometimes happened, the drifts could be much deeper than a few millimeters.

As near suspension as some fines were, in an hour all but the very finest had fallen out of the air and onto them. After that it was only a hazy afternoon, windless, the air filled with something like a thin smoke, so that they could see the whole of the basin; which was covered with a lumpy blanket of dust.

Nirgal went out with his mask on as always, and dug desperately with a shovel, then with his bare hands. Sax came out, staggering through the soft drifts, to put a hand to Nirgal’s shoulder. “I don’t believe there’s anything that can be done.” The layer of dust was about a meter deep, or deeper.

In time, other winds would blow some of this dust away. Snow would fall on the rest of it, and when the snow melted, the resulting mud would run over the spillways, and a new leaf-vein system of channels would cut a new fractal pattern, much like the old one. Water would carry the dust and fines away, down the massif and into the world. But by the time that happened, every plant and animal in the basin would be dead.

Part 9: Natural History

Part Nine

Natural History

Prologue

Afterward Nirgal went with Sax up to Da Vinci, and stayed with the old man in his apartment. One night Coyote dropped by, after the timeslip when no one else would have thought to visit.

Briefly Nirgal told him what had happened to the high basin.

“Yeah, so?” Coyote said.

Nirgal looked away.