The valley below the cliffs is green with fresh grass, the sage brush and desert plants replaced by new fields for crops and grazing. Earth is a wetter place since the oceans rose. Many of those who survived the decades without summers moved away from the old towns and cities looking for places to farm and settle in peace.
Peace was not easy to find in the early days. Bands of nomads using the last of the fuel and vehicles raided and plundered any undefended farms, unless they were well hidden and away from the roads. Even out here in what had been wilderness the first settlers had to fight off attacks. When firearms and ammunition had run out older forms of weapons had to suffice. Generations had passed but there was still a lookout posted at the top of the cliff. These days the lookout only carrying a bow and arrows for defence and a horn to sound the alarm. No one could remember that last time the horn had sounded in earnest.
Lowell watched the sundial creep slowly round to noon and noticed that the sand had almost run through the timer, another quarter hour. Lookout duty was boring but it still was easier than ploughing or weeding. Time to lift the ancient binoculars and check out the horizon for the last time in his watch. Then he could yell out the noon all clear and Freddy would make his way from the cliff top camp and relieve him. Just as long as Freddy had not scoffed all the lunch, again. It was Trina's turn to cook today and Lowell's mouth watered, when he was old enough she would make a great wife.
As he was about to put down the binoculars Lowell noticed a faint dust cloud, perhaps a mile or so away, to the south-west, near where the old town of Camp Verde had been. The nearest settlement in that direction was Prescott. It could be a trading party from there. The old telescope gave him a better view. They were just approaching a bend in the river, three loops upstream. Five or so riders and a wagon. No flag though. Prescott folk always carried a green flag. Lowell hesitated, with his hand on the horn around his neck. Raising it to his mouth he blew, a sound like a tiny kitten came out of the horn. His mouth had gone suddenly dry. A quick swig from his canteen and the alarm horn sang out over the cliffs and fields.
Faces peered up from the fields below. Freddy, Trina and Carla came at a run from the nearby camp. Lowell pointed at the approaching group and looked through the telescope while Carla pulled the red semaphore flags from their container.. "Five, no, six riders and a wagon, about a mile and a half south-west, no flag showing." Lowell said. Carla's arms worked the flags and below them horses were being saddled and arms handed out. Two teams of oxen were being harnessed to the barriers that could be pulled across the main path in and out of the settlement and already a line of armed villagers were assembling there.
As soon as the village's riders headed out along the path the oxen started pulling the heavy spiked barriers into place, leaving only a gap wide enough for a single rider to pass. Another shorter fence was being man-handled into place behind the gap. All Lowell and the other lookouts could do was watch and wait ...