I have two alfa romeos, a 145 and a 156 and they both suffer from sticking handbrakes this time of the year, it's a common problem.
Both have the same type of hand brake cables and they are sealed when new, once worn or a stone has pierced the outer sheath water/condensation gets in and can freeze in the winter sticking the hand brake on, i just never put the hand brake on when parking one up.