Is a hazardous White Christmas on its way?
For anyone in the UK, it won’t have gone unnoticed that the temperature has suddenly plummeted. We experienced a relatively balmy November (with a 2022 UK average of around 10°C), only to be rapidly thrust into sub-zero temperatures, with snow flurries in the north and east, and a widespread layer of frost nationwide (which in some cases has persisted throughout the day). Such temperatures, which widely dipped to -7°C last night, are well below those expected for this time of the year (2-7°C).
Whilst such frosty conditions create some beautiful scenery, such temperatures are pretty hazardous and can pose a significant risk to health. In response, the Met Office has issued a Yellow National Severe Weather Warning for snow and ice, while the UK Health Security Agency issued a Level 3 “Severe Cold Weather Alert”, active until Monday 12 December (there are only four levels, with the next being a National Emergency). These warnings are announced to ensure the relevant authorities are aware and ready to act as necessary.
The advice currently being issued to help mitigate the cold hazard is for everyone to maintain an inside temperature of at least 18°C, with the elderly, and those with pre-existing conditions, being particularly vulnerable to lower temperatures. For those venturing out, wearing numerous layers of clothing will assist in trapping as much heat near the body as possible, along with using accessories such as scarves, gloves, and hats. Drivers are advised to check recent weather forecasts and indeed, to review whether or not their journeys are actually necessary; they should also check the tread on their tyres and only venture out with a blanket (for emergency use). Something people should also consider is to ensure their mobile phone is completely charged so that they can contact the emergency services, should that be necessary.
These cold conditions have trigged Cold Weather Payments for those eligible in England and Wales and Winter Heating Payments for those eligible in Scotland. Such payments could mean the difference between heating one’s home, and not, and in turn, between life and death for some people. In fact, “heat-banks” have been set-up in some locations, to provide a warm environment for those who cannot afford to heat their homes adequately or, indeed, for those who have no homes to heat. The Energy Crisis really couldn’t be happening at a worse time.
So what is causing this exceptional cold blast?
Simply put: it’s the Greenland Block (or more formally, a negative North Atlantic oscillation (NAO). This phenomenon consists of a high-pressure system being sat over Greenland, messing up the ‘normal’ meteorological patterns of this time of year. High-pressure systems (or anticyclones) generate a clock-wise atmospheric rotation and, with such a system being centred over Greenland (the red region in the map below), cold, Arctic air is being drawn south, toward us, bringing with it these extremely cold conditions.
And odds for a White Christmas?
Well, should such conditions continue, they could easily bring us a White Christmas. However, most climate models and meteorologists are predicting that it will dissipate next week, bringing out temperatures back in line with where we’d expect them to be for this time of the year. This will be welcome news to the vulnerable of society but will of course, disappoint those dreaming of a Bing Crosby-style Christmas.