The death toll from the flash floods that devastated central Texas on Friday has risen to over 100, with many others still unaccounted for.

Heat-related warnings were in effect across 21 states on Thursday, as the National Weather Service (NWS) cautioned millions of Americans about "dangerously hot conditions" in multiple regions.

The US National Weather Service (NWS) issued winter weather-related warnings for 28 states on Wednesday morning, as up to 14 inches of snow is expected to fall in certain regions of the region.