第5章 The Countdown

They worked through the afternoon by the light of the flashlights and the shrunken sun, mapping Ibarra's notebook and the recorded bursts into one shared table. Omar's first breakthrough was the encoding. The log carried a field guide at the back—a single page of Ibarra's cramped handwriting, headed *relay frame format*, and under it a list of pulse shapes mapped to values. A short beep was zero. A long dash was one. Two medium pulses bracketed the frame. It was not a cipher at all. It was a number written in the oldest form of telegraphy, meant to be read by anyone with a radio and a pencil. "Every burst we logged decodes to one number," Omar said, filling the last column of his table. "Here's the sequence: 410, 402, 389, 371, 348, 317, 284, 249, 212. Nine measurements. One every hour on the hour, smoother than any instrument I've ever calibrated." "Nine measurements of what?" "Ibarra's field guide calls it the approach rate. The array measures the distance to the moving rupture front—the segment of fault that is currently slipping, propagating toward the coast. Each measurement is the remaining distance in thousands of feet from the fault trace to the array." Juna ran the numbers in her head. "410 to 212 in eight hours. It's speeding up." "It is accelerating almost perfectly. Linear in the earlier readings, exponential now." Omar shut his eyes, did a long division on the page, and opened them. "At this rate it reaches zero in eleven to thirteen hours." "That's not days. That's not two days." "That's dawn." Omar set his pencil down with the enormous gentleness of a man putting a live fuse on a table. "Dawn, at the top of the rising tide, when the water over Signal Rock stands highest. Ibarra built the relay to predict exactly this. The second rupture completes at slack high water, and when it completes, the displaced volume dumps into the bay—the wave the first surge only previewed. The countdown isn't a countdown to a warning. It's a countdown to the impact." Juna stood up. Her hand found the doorframe for no reason she could name. "You said eleven to thirteen hours." "Between eleven and thirteen." "Then we have twelve hours to move forty people off a ridge." She looked out at the gray water, at the drowned town, at the cliff of Cathedral Ridge where the school roof sat higher than anything for miles. "The school is at the evacuation height. The county drilled it as safe." "The county had a paper from 2008 that said the slope and the bluff gave you forty extra feet of clearance," Omar said. "I helped write a version of that paper's successor. The runup calculations used the offshore model, not the trench model. If the second rupture is bigger than the first—and the acceleration profile says it is—then the forty feet of clearance is more like fifteen. The ridge road floods. The school yard floods. We move them, or we count on luck nobody gets twice." "Move them where?" "Upper cathedral. The fire lookout." He pulled the familiar page from his ledger and drew a cross on the highest contour. "Cathedral Peak. The summit of the ridge—a good hundred feet higher than the school's ground. The ridge road runs to within a quarter mile of it, and then it's a goat trail, but it's dry ground and it is high." "From the school to the peak, carrying kids, at night, in the dark—" "Or we wait at the school and gamble fifteen feet." Omar's voice did not rise. It dropped instead, the way it did when he was being exactly as calm as the situation was not. "Several hours of margin is all I can offer you. Minutes, if we waste the afternoon." Juna looked at the clock. It was 1620. The town hall clock, recovered from the shed, ran on a spring and was keeping faithful time, the only clock in Tidefall that had not stopped in the water. Dawn was roughly seventeen hours away. The countdown said the wave would beat dawn by an hour, maybe two. She had twelve hours. She had a quarter mile of goat trail. She had thirty-one people on a school ridge, and a drowned town full of people nobody had counted, and a radio that could not reach farther than the next hill. "All right," she said. "We go to the school tonight, we move everyone to the peak, and we do it before the countdown hits zero. And you stay on the tower." "Juna." "You stay here and you listen to the machine. When it broadcasts again, you log it. Every hour on the hour. If the number drops faster than the curve—if it breaks the acceleration—you do not wait for dawn. You key the landline on the hill line we stole from the shed—" She tapped the hand-cranked field telephone they had found in the harbor locker and wired, in a long afternoon of Omar's patient fiddling, to the school's surviving landline pair. "—and you tell whoever's left to run." "And you?" "I'll be on the trail with the rear of the line. That's what SAR does." She pulled on her fins, checked her knife, and went out to meet the evening. The walk to the ridge took her two hours and change: along the drowned shoulder of the highway, across the one intact culvert, up the switchbacks where the road climbed out of the flood. The sun set behind her as she climbed, and behind her, to the southwest, the open sea held the dusk exactly the way it had held the dawn—flat, indifferent, keeping its second punch in a deep vault that was filling itself, hour by hour, number by number. She reached the school at half past eight to find the ridge quiet and the roof lights out, the survivors gathered around a single camping lantern in the gym. The school secretary, Mrs. Aughrim, was older than she looked and sharper than she seemed. She took the news of Cathedral Peak without blinking. "We'll pack before first light and move at dawn," Juna said. "We'll move tonight," Aughrim said. "The children can carry the water. The dark is one problem. The next wave is another, and the dark has never killed anybody if they walk slow." They had the gym packed in an hour. They were on the ridge road by ten, a chain of thirty-one people and seven children strung between the school and the peak, and somewhere behind them, invisible on the harbor's drowned floor, the machine on Signal Rock ticked through another frame. Juna walked at the rear with the flashlight off, listening to the water talk to the shore, and counted the miles until morning.