Seven years later, the Salmon River is still running orange, but it's not alone in its dramatic change of hue. More than 200 formerly clear streams and rivers across the Brooks Range have gone orange and cloudy, most within the last 10 years. While this phenomenon isn't entirely new to science, the sudden uptick in orange waterways is thought to be the result of thawing permafrost, a phenomenon that is accelerating with climate change. The rusty influx comes from iron, once trapped in frozen ground but now released by warming earth and flooding into the watershed. Alongside it, scientists have detected toxic levels of metals like copper and zinc"all of which are threatening wildlife, people, and ways of life that have persisted for millennia.