Hugo Chavez is going to make it rain

Last a summer, Chinese government officials worried that it might rain on their parade, literally, during the Olympics. They fired rockets filled with dry ice and silver iodide into the clouds, to make them cough up any raindrops before Beijing. The process might have backfired, causing two fierce snowstorms. But Moscow's mayor seems undeterred by the weather -- he is using the same technology to deflect snowfall from his city, having military planes spray iodide clouds.
more info:
http://blog.foreignpolicy.com/posts/2009/11/16/hugo_chavez_is_going_to_make_it_rain