Although 30° isn't really cold, I often put 2-3 drops of lighter fluid in the carb when the weather is cold. They'll start up just fine then. If you can turn the prop by hand, but the starter won't turn it over, I'd suspect a low or dead starter battery. Do you use a power panel? Is your glow igniter fully charged?
Here's some really nice floats http://www.valleyviewrc.com/ . Go about 1/2 way down the page. They'll work OK on fresh soft snow, but don't use them on old hard snow that is crusty, it'll tear the crap out of the 'em.