Hidden hazards

FOR YEARS, SMALL PLANES have buzzed across the skies of Washington carrying specialized instrument packages that peer down through the belly of the aircraft. As they soar above mountains, rivers and valleys, the machinery paints the topography below with laser light thousands of times per second, reflecting the contours of the landscape back to onboard sensors as data, which is later processed to create detailed scans of the terrain.

This technology is known as LiDAR — Light Detection And Ranging — and the flights are