[Lawtan]

Well, for one, it mixes Sci-fi with the sort of 50's horror. For another, it has an interesting twist on the nombies (Meant to type zombies, but mistyping left this funny variation - NOMBIES! Nom nom nom). Finally, you leave on a semi-cliffhanger, which often good horror does to various degrees (and bad horror tries to do and fails).

Some "show, not tell" would help, as would splitting up the paragraph to make it more readable (one may help the other). In other words, describe the despair felt at the cries of babes and women shrieking out in terror over the frozen earth shadowed by near-endless nights, until they died away in the morn. Build up the paranoia felt by the farming family, by spoken words.