Dangerous, lake-effect snowstorm freezes western and northern New York

Lake-effect snow, caused by frigid air picking up moisture from warmer lakes, prompts driving ban and state of emergency

A dangerous lake-effect snowstorm has paralyzed parts of western and northern New York state, with more than 1ft of snow already on the ground on Friday morning in places and a driving ban keeping people off the roads in the Buffalo area.

The worst snowfall was expected in Buffalo, where the National Weather Service said up to 4ft might fall in some spots through Sunday, with periods of near-zero visibility.