Abstract: Snow blankets 30% of Earth’s land surface (60% of northern hemisphere land) in midwinter, dramatically changing our planet’s land surface and affecting our weather for months. Seasonal snow is critically important to society for the management of water resources, natural hazards, water security, and in many economic sectors. The only practical way to estimate the quantity of snow on a global scale is through satellites. Despite 4 decades of satellite observations, the highly variable nature o…