Cloud seeding is one of those ideas that seems useful and obvious. Just sprinkle particles from a plane flying through storm clouds, and moisture will condense around the particles and fall onto the ground as rain or snow. Voila: Drought is ended or ski season is saved!
The reality, however, is that nobody has ever been able to prove that it really works. For one thing, it’s hard to know whether the clouds would have rained anyway; for another, it’s hard to even know which cloud you’ve seeded because they break up and merge and move in difficult-to-follow ways.
So I was interested to see that researchers at the University of Colorado Boulder ran three experiments using radar and ground measurements to “quantify the spatial and temporal evolution of snowfall generated from glaciogenic cloud seeding of winter mountain cloud systems and its spatial and temporal evolution.”
in other words: Did it work and if so, how much? “The team showed that their three cloud seeding experiments produced enough precipitation to cover 571 football fields in a foot of water” says this short item.
That sounds pretty good. How long before Loon and Waterville Valley are hiring cloud-seeding aircraft to boost their snowfall totals?
New Hampshire once flirted with a ground-based version of cloud seeding. A state employee fired 29 cloud-seeding machines in 1964 (gas-fired burners that vaporized silver iodide in hopes it would drift aloft and turn into droplets) but the results were, no surprise, inconclusive. I wrote about this as part of another story – read it here.