New York Times: When Lewis and Clark first encountered the Columbia River in 1805, they wrote about nearby streams so thick with salmon that you could all but walk across on their backs. Last summer, those streams looked very different. As a torrid heat wave settled over the Pacific Northwest, the salmon heading up the Columbia River from the ocean in their ancient reproduction ritual started dying en masse, cooked in place by freakishly hot water that killed them or made them vulnerable to predators. Sockeye died...