Tom Painter, a scientist with NASA’s Jet Propulsion Laboratory left , with Frank Gehrke, state snow survey chief, in the flying laboratory. Starting in early April, researchers have made weekly flights over the upper Tuolumne River basin, taking sophisticated instrument readings of the snow depth and reflected sunlight. The information, coupled with data from the ground measurements, promises to paint the most comprehensive snowpack picture that water managers have ever had. Credit: California Department of Water Resources