7 weather phenomena that have already marked 2023
While 2022 was marked by record heat and drought, the first quarter of 2023 is already witnessing several extreme weather events that have meteorologists wondering. These include:
Freddy, the most persistent cyclone ever observed: cyclone Freddy, which hit Malawi, Madagascar and Mozambique, will have lasted 36 days, from February 5 to March 15, moving across the Indian Ocean. It is the most powerful cyclone measured with the ACE index which measures the amount of energy emitted by cyclones.
The succession of atmospheric rivers in California: the region has experienced the passage of about fifteen atmospheric rivers since December 2022. These phenomena have caused flooding and significant snowfall, 17 meters of snow at an altitude of 2,000 meters for example at the Mammoth ski resort in the Sierra Nevada.
A dry winter in a large part of Southern Europe: In France in particular, the rainfall deficit reached -3% in January and -74% in February due to the presence of a powerful and persistent anticyclone, and the precipitation that returned in March did not allow for the proper recharging of groundwater. Spain, Portugal and Italy experienced similar situations, with canals in Venice drying up due to exceptional tides and high pressure that compressed the water in the Mediterranean.
Extreme flooding in New Zealand: Auckland experienced historic flooding in late January, with 241 mm of rain falling in 24 hours, eight times the amount of water the city usually receives in January. The passage of an atmospheric river over New Zealand was aided by warming oceans and the presence of a high-pressure system that slowed its advance.
A record drought in Africa: the Horn of Africa is experiencing the longest and most intense period of drought, some countries such as Kenya, Ethiopia or Somalia recorded a sixth rainy season without rain. The situation is causing regional conflicts and increasing the number of climate refugees, with the UN estimating that 3.3 million people are in need of emergency aid due to the lack of water.
A record cold in the United States: in February New Hampshire recorded a felt temperature of -78˚C, calculated by taking into account measurements taken at an altitude of 1,900 meters, with a recorded temperature of -43˚C and wind gusts of 200 km/h.
Over this area, the polar vortex weakened and the zone that delimits the stratosphere lowered to 1,900 meters allowing stratospheric winds to infiltrate.
Several Mediterranean hurricanes: several medicanes, the Mediterranean hurricanes, have formed since January but unlike other hurricanes, it is not the water temperature that plays an important role in their formation but rather the cold air present aloft when it encounters a depression. These hurricanes usually form between September and November.
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