With its freezing temperatures and shortened days, winter is not many people’s favorite season. At the heart of this season, cold waves, which can paralyze entire populations and sectors, are feared.
Cold snap or cold wave: what’s the difference?
These two meteorological phenomena are not to be confused. The cold snap occurs in winter, generally from October to May, over a short period of 1 to 3 days with temperatures 2 or 4°C lower than the seasonal average.
In the same way as a cold snap, a cold wave is characterized by abnormally low temperatures compared to seasonal norms and a duration of several days or weeks, in the period from November to March. But a cold snap is an extreme weather phenomenon that requires different conditions:
The biggest cold waves date from the winters of 1956, 1963 and more recently 2010. For the latter, it is the Center region which was particularly affected with -15°C in Orléans and -13°C in Châteaudun.
This lingering cold air mass is typically associated with severe winter weather conditions. The temperatures are freezing, the winds are strong, the snowfall is heavy, the ice is omnipresent… The consequences are significant on daily life, agriculture, energy, transport and even the health of the populations concerned.
What are the different types of cold waves?
A cold snap occurs when atmospheric circulation is disrupted on a large scale. Then, several weather conditions are observed during this period as well as different sources of cold air masses. There are 4 main types of cold snap:
These cold waves can arrive from the north, that is to say the polar and arctic regions, but also from Siberia or Russia, which are closer. There are also oceanic cold waves which occur when masses of cold air coming from the sea move towards coastal regions. These cold spells can be accompanied by humidity and precipitation.
What are the characteristics of a cold snap?
A cold snap is characterized by abnormally low temperatures compared to the season, particularly with negative temperatures at night. Unlike a brief drop in temperature as is the case with a cold snap, a cold snap persists for an extended period of time. It is frequently accompanied by strong winds which increase the feeling of cold.
A cold snap favors heavy snowfall, the formation of frost and black ice, etc. Since atmospheric conditions are unstable, other weather phenomena may occur such as snowstorms or blizzards.
What causes cold waves?
All of these weather patterns can create blockages in the atmosphere and therefore lead to stagnation of cold air masses. The mountains in certain places also accentuate this blocking phenomenon.
What is the impact on health and society?
A cold snap is an extreme weather situation that can have significant consequences on people’s daily lives.
Impact on population health
Since a cold spell lasts several days or weeks, prolonged exposure to freezing temperatures can lead to loss of body heat and therefore risk of hypothermia.
The extremities of the body are particularly vulnerable. Fingers, toes, noses and ears are put under strain and susceptible to developing frostbite.
Cold air irritates the respiratory tract and increases the risk of respiratory illnesses. Homeless people are particularly vulnerable during these cold waves. Emergency shelters are being set up with distribution of clothes, blankets and other essential supplies.
Impact on transport and the economy
Transport may be disrupted with delays, cancellations, accidents and driving difficulties. Accumulating snow and ice can damage power lines and infrastructure, causing power outages. As cold spells lead to increased demand for energy for heating, electricity networks can also be overloaded.
These transport, energy and snow problems impact all types of infrastructure, particularly businesses and public services. The latter may be forced to close while waiting for the cold snap to pass or to adapt working conditions (teleworking, staggered hours, etc.). Slowdown in production and financial losses are possible. Agricultural crops can also be heavily damaged by cold, frost and snow, which has consequences for livestock or harvests.
Impact on fauna and flora
Cold spells weaken plants and animals and can lead to their destruction. In cases of intense cold, watercourses freeze and cause flooding due to ice jams. The ice formed creates an obstacle and blocks the natural flow of a river. Water builds up and since it cannot circulate normally, it eventually overflows. This rising water causes flooding of the surrounding banks and possibly the homes located there.
In order to best cope with these cold waves, the authorities monitor weather conditions to warn the population in advance. All emergency services are mobilized to manage road accidents, power outages and health problems. During a cold snap, you need to stay informed, keep in touch with your neighbors, avoid unnecessary travel and stock up on water and food. In the event of power outages, flashlights, batteries, candles and blankets will also be welcome.