Extreme weather and life-threatening cold temperatures are set to hit western states near the Rocky Mountains – after severe flooding killed at least 10 people in the eastern US over the weekend.
The National Weather Service’s (NWS) weather prediction centre said a winter storm tracking from the Central Plains to the Mid-Atlantic is expected to strike later this week.
On Tuesday, temperatures in northeastern Montana are predicted to dip as low as -42.7C, along with a wind chill that could reach -51C.
Elsewhere, the weather service said wind chill temperatures as low as -45.6C were expected in most of North Dakota, which remained under an “extreme cold warning,” along with large parts of South Dakota and Minnesota.
A runner in heavy snow in Alameda Avenue at Marion Parkway, Colorado. Pic: AP
It marks the 10th – and coldest – polar vortex this season so far, with pressure systems pushing cold air from the Arctic southwards into North America and Europe.
What is a polar vortex?
The polar vortex is a large area of low pressure and cold air surrounding both of the Earth’s poles and refers to the counter-clockwise flow of air that helps keep the colder air near the poles.
This occurs regularly during winter and is often associated with large outbreaks of Arctic air in the US.
In a post on social media, the NWS said the weather system “will produce a swath of both heavy and disruptive snowfall”.
‘Frostbite within minutes’
It also said that “a bitterly cold air-mass containing dangerous wind chills temperatures looks to stretch from the Great Plains to the northeast” – and that there is “high confidence for widespread, record-breaking cold” in the central states.
The NWS added: “Wind chills between -30F and -60F are expected across the northern Plains, lingering for multiple days.
“These extreme conditions can cause frostbite within minutes. Sub-zero wind chills will likely extend as far south as Texas, Arkansas, and western Tennessee and Kentucky.”
Avalanche warnings were also issued for numerous areas of the Rocky Mountains stretching from Colorado to Washington state, with the danger rated highest in Utah.
Kentucky floods kill at least nine
It comes after flooding in the eastern states killed at least 10 people, with nine deaths – including a mother and seven-year-old child – reported in Kentucky and one death in Georgia.
Cars sit in floodwaters at a railroad underpass in Louisville, Kentucky. Pic: AP
Kentucky Governor Andy Beshear said on Sunday that the storm was “one of the most serious weather events we’ve dealt with in at least a decade”.
He added in a post on social media: “We need Kentuckians to remain alert. There are more than 300 road closures, with leaders saying the statewide impact is historic.”