A rare winter storm is bringing snow and freezing rain to parts of the US deep south, closing highways and airports in Texas and prompting a first-ever blizzard warning in southwest Louisiana.

Four people are thought to have died from cold exposure so far - two cases are being investigated as cold-related by Austin authorities in Texas, while two deaths from hypothermia were reported in Georgia and Milwaukee.

Up in the country’s north, parts of New York state are being hit by another storm, blanketed by up to 18 inches of snow.