Flurry of snowballs is great when you get it but doesn't scale at all, not even with intensify spell. Chill touch is not a cold spell; frostbite is.
Winter's grasp (witch 2) is a good AoE debuff with rime spell. Better than flurry because it has range, area and a lingering effect. You get ice storm as a 3rd level spell as a winter witch (at 6th class level) and it would be OK to specialise in too, at least at first. Ice spears (witch 3) might be better in the long run, but it's not great until you have a couple of spears (CL 8). Snowball (witch 1) would be possibly the best choice for pure damage. Witch blasting spells do suck.
Oh ya, ice Spears would take some time but even with just 1 it would be pretty sweet.
No aoe debuffing like flurry can do though, by level 8 at least two specific targets can be hit