Juneau, Alaska went from buried in snow to rushing floodwater in the middle of winter. After a historic snowstorm stacked snow feet deep across the city, a warm atmospheric river moved in and flipped the script. Rain fell directly onto the snowpack, melting it rapidly and turning streets into fast-moving rivers of slush, mud, and ice. This isn’t river flooding. This is rain-on-snow flooding — one of the most dangerous winter weather setups. When saturated snow collapses all at once, the water ha