( Blizzards ( ( are ( ( severe ( winter storms ) ) ( characterized ( by ( ( ( heavy snow ) and ) ( strong winds ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Blizzards)) (VP (VBP are) (NP (NP (JJ severe) (NN winter) (NNS storms)) (VP (VBN characterized) (PP (IN by) (NP (NP (JJ heavy) (NN snow)) (CC and) (NP (JJ strong) (NNS winds))))))) (. .)))
Blizzards are severe winter storms characterized by heavy snow and strong winds.
(ROOT (S (NP (DT A) (NN winter) (NN storm)) (VP (VBZ is) (VP (VBN called) (NP (DT a) (NN blizzard)))) (. .)))