Replying to Snow won't pack

I'm somewhat a beginner in the self-made rail type of stuff. Here in chcago, the snow is ussually pretty good packing snow and I have no issue building a drop in, and lip for my rail. However, we have been hitting some extreme cold and last night all my stuff started falling apart when I hit it. I put a lot of new snoww down and watered it down, but now it all looks like shit because its all falling apart. Anyone have tips on how to make it all stay together better? I'm thinking I might just do layers of snow and watering.