Mission

A snowflake is born when water vapor clings to a particle of dust or smoke and the resulting droplet turns directly into ice. Problem is that is there's only so much water vapor in a cloud to go around. In clean clouds there is less dust and smoke particles, so the droplets that form are bigger. In polluted clouds there's a lot more particles for the limited water vapor to cling to, so although more droplets form, they are smaller.  Unfortunately often these smaller droplets aren't heavy enough to fall out of the cloud at all and just end up floating right along with the cloud until they evaporate on the side of the mountains, never adding to the local snowpack.  A 2004 study concluded that downwind of major metropolitan areas, air pollution suppressed precipitation in clouds by 15 to 25%.  We believe snow is a gift, and we need to treat it as such. That's why we founded Winterfaith, to raise awareness about this unique link between air pollution and snow. Breathe deep, ski deep. Visit ucair.org to find out how you can help.