Geologists are still piecing together their timeline for just how the disastrous deadly mudslide in Oso, Wash. last weekend went down and are mapping out how previous slides changed the surrounding landscape. Last Saturday, mud and debris swept down a rain-soaked slope, crossing the Stillaguamish River's North Fork and leveling homes and buildings on its far side. Seventeen people have been confirmed dead while scores more remain missing, and crews are still combing the area carefully for bodies. Seismic readings show that the hill collapsed in two stages, with the first collapse letting loose a wave of debris that one expert says probably caused most of the deaths. It also destabilized the upper slope, which collapsed four minutes later and set off a smaller seismic shock. Click through to read more.