Google Adsense code automatically adds some malicious attributes to all DIV tags:
max-height:auto !important; height:auto !important
This destroys the responsiveness of mobile viewing experience. I'm not using Snowflat theme, but this will surely affect every theme.
I tried several ways to overcome this, but they don't work (or no longer work). I also voiced anger on Adsense forum, and it turns out that many people out there are also pissed. So as the last resort, I had to eliminate Google Adsense code from side panel in mobile view.
So, you can try using qa_is_mobile_probably() function to display Google Adsense ads selectively.
Another method is you can create a different mobile theme. Just clone your Snowflat theme and name it as Snowtap theme, and you use Snowtap for mobile users. In Snowtap theme, you don't include Google ads in sidepanel.