Texas (coldwave)

During winter months, another ring of strong west winds encircles a pool of extremely cold air that sits over the high latitudes like a “spinning top” over the North Pole – this is the stratospheric polar vortex (Erdenesanaa, 2022). Occasionally this vortex can become disrupted and either elongated or broken into smaller swirls. When this happens, it can alter the behaviour of the jet stream, such as unusually large southward dips, bringing severe cold events to North America and/or Eurasia, sometimes simultaneously.

Recent research suggests these disruptions to the vortex are happening more often in connection with a rapidly warming and melting Arctic, which we know is a clear symptom of climate change. This means that cold spells may occur more frequently and trigger particularly long-lived events in regions unaccustomed to disruptive cold (Cohen et al., 2021), unless we can curtail our emissions of heat-trapping gases dramatically and quickly.

For example, the cold blast of February 2021 that brought Texas to a standstill saw temperatures 22.4°C below normal (Erdenesanaa, 2022). Temperature records were broken throughout the state, including lows in Austin (-14.4°C), Dallas (-13.3°C) and Houston (-12.2°C) (FERC, 2021). Beyond the extreme temperatures, Texas recorded nearly 150 deaths and more than US$20billion in damages (Henson, 2021).

On the link between Arctic warming and mid-latitude cold snaps: “The Texas cold blast of February 2021 is a poster child.” 

-Dr Jennifer Francis, Woodwell Climate Research Center (Borenstein, 2021).

Such extreme winter weather events linked to stratospheric polar vortex disruptions – associated with  Arctic change in sea ice and snow cover in fall – highlight the need for (innovations in) forecasting and early warning systems in local and regional disaster risk reduction efforts (Arctic Risk Briefing, 2021).

Read more about extreme weather here.