In California, authorities have lifted a mandatory evacuation order, allowing tens of thousands of residents near the Oroville Dam to return to their homes. Nearly 200,000 residents living near the nation’s tallest dam were forced to evacuate over the weekend, after erosion caused a hole to open up in the dam’s emergency spillway, threatening to unleash a “30-foot wall of water” onto nearby towns. Environmental groups had warned California officials more than a decade ago that the Oroville Dam’s emergency spillway was at risk of erosion, but the officials ignored the warnings. Scientists say this season’s record-breaking levels of rainfall in California, which has filled the Oroville Dam to the brink, is one of the latest examples of extreme weather caused by climate change.