Snow cannons are few and far between in Bulgaria and even where there are cannons they can only be used at certain temps. Cannons blow fine droplets of water into the air that freeze and drop as snow. Anything less than -3 and the water does not freeze to form snow. Anything more than -10 and it falls as ice.
Thanks Pete
PS
Great site, I have learnt so much about skiing in Bulgaria from it, just looking forward to 23rd Dec to experience the atmosphere.
Regards
Will