A team of scientists is firing lasers from aircraft to measure snowpack across the US West, and what they are finding is alarming. The snowpack in many mountain basins has dropped to critically low levels, threatening the water supply for millions of people. These high tech missions are revealing the scale of loss in real time.
Aerial lasers reveal the hidden scale of snow loss
The technology, known as lidar, works by bouncing laser pulses off the ground and snow surface from a plane flying overhead. By comparing the two measurements, researchers can calculate snow depth with remarkable precision across vast, remote areas. The flights cover hundreds of miles of mountain terrain that would take weeks to survey on foot.
Why the West depends on every flake
In the United States, the western states rely heavily on snowpack that accumulates in the mountains during winter and melts slowly through spring and summer. That meltwater fills reservoirs, irrigates farmland, and supplies drinking water to cities from Denver to Los Angeles. This year, the snowpack in several key basins is far below the historical average, and some areas are approaching record lows.
The missions are led by scientists from NASA and several universities. They have been flying over the Sierra Nevada, the Rocky Mountains, and the Cascade Range. Local water managers and farmers are watching the data closely because it directly affects decisions about water allocations and drought declarations. The low snowpack means less water will be available later in the year.
What the numbers show so far
The lidar surveys have documented snow water equivalent, the amount of water contained in the snow, at levels that are 50 to 80 percent of normal in some basins. In a few locations, the snowpack is the lowest ever recorded for this time of year. The measurements are more accurate than older methods that relied on ground sensors and manual snow courses.
These flights are part of a broader effort to understand how the region's water cycle is changing. The data will help cities and farms plan for coming months. For now, the laser readings confirm what many had feared: the West's frozen reservoir is shrinking fast.
