She laughed. He grabbed the cockpit handrail, pulled himself up to her side. He saw immediately what she meant; the wind was strong, perhaps sixty-five kilometers per hour, and the whine in the boat’s minimal rigging was loud and sustained. There were whitecaps everywhere on the blue sea, and the sound of the wind coursing through all that broken water was very unlike what it would be pouring over rock— there it would be a high keening shriek— here, among the trillions of bursting bubbles, it was a deep solid roar. Every wave was whitecapped, and the great hills of the ground swells were obscured by foam flying off the crests and rolling in the troughs. The sky was a dirty opaque raw umber, very ominous looking, the sun a dim old coin, everything else dark, as if in shadow, though there were no clouds. Fines in the air: a dust storm. And now the waves were picking up, so that they spent many long seconds shooting up the side of one, then almost as many schussing down into the trough of the next one. Up and down in a long rhythm. The positive interference Ann had spoken of made some waves doubly big. The water not foaming was turning the color of the sky, brownish and dull, dark, though there was still not a cloud to be seen— only this ominous color of the sky; not the old pink, but more like the dust-choked air of the Great Storm. The whitecaps ceased in their area and the sound of water against the boat grew louder, a slushy rumble; the sea here was coated with frazil ice, or the thicker elastic layer of ice crystals called nilas. Then the whitecaps returned, twice as thick as before.

Sax climbed down into the cockpit and checked the weather report on the AI. A katabatic wind was pouring down Kasei Vallis and onto Chryse Gulf. A howler, as the Kasei fliers would say. The AI should have warned them. But like many katabatic storms it had come up in an hour, and was still a fairly local phenomenon. Yet strong for all that; the boat was on a roller-coaster ride, shimmying under hammer blows of air as it shot up and down on the huge groundswell. To the side the waves looked like they were being knocked over by the wind, but the boat’s skittering flights up and down showed that they underlay the flying foam as big as ever. Overhead the mast sail had contracted almost to a pole, in the shape of an aerodynamic foil. Sax leaned over to check the AI more closely; the volume knob on the beeper was turned all the way down. So perhaps it had tried to warn them after all.