Meteorologists predict a wild, wet winter for much of the world, thanks to this year's El Niño, which ties with the 1997-1998 season as the strongest recorded. The weather phenomenon happens every few years when the Pacific Ocean warms up around the equator, changing weather worldwide.

This year's powerful El Niño has already caused severe floods in many South American countries. More than 100,000 people were forced to evacuate their homes in areas bordering Paraguay, Uruguay, Brazil and Argentina after floods due to heavy summer rains.

El Nino flooding
A church is partially submerged in floodwater in Alberdi, Paraguay, on 5 January 2016Jorge Adorno/Reuters
El Nino flooding
A cat sits inside a flooded building in Asuncion, Paraguay, on 28 December 2015Jorge Adorno/Reuters
El Nino flooding
A lifebuoy hangs from a window in a flooded house in Asuncion, Paraguay, on 27 December 2015Jorge Adorno/Reuters
El Nino flooding
A submerged home is pictured in Asuncion, Paraguay, on 27 December 2015Jorge Adorno/Reuters
El Nino flooding
Floodwaters make the figures in a mural reading "Justice" seem as if they are swimming in Asuncion, Paraguay, on 27 December 2015Jorge Adorno/Reuters
El Nino flooding
A woman and her son sit next to a makeshift shelter in Asuncion, Paraguay, on 27 December 2015. More than 100,000 people have had to be evacuated from their homes in the border areas of Paraguay, Uruguay, Brazil and Argentina due to severe flooding in the wake of heavy summer rainsJorge Adorno/Reuters
El Nino flooding
A man travels on a makeshift raft past flooded houses in Asuncion, Paraguay, on 27 December 2015Jorge Adorno/Reuters
El Nino flooding
Residents remove their belongings on a boat from their flooded houses near the Paraguay river in Asuncion, on 27 December 2015Jorge Adorno/Reuters
El Nino flooding
People travel on a boat past flood-affected houses in Asuncion, Paraguay, on 27 December 2015Jorge Adorno/Reuters
El Nino flooding
A flooded football field is seen near the Paraguay river in Asuncion, on 31 December 2015Jorge Adorno/Reuters
El Nino flooding
A dog stands on the roof of a house in a flooded neighbourhood in Asuncion, Paraguay, on 30 December 2015Jorge Adorno/Reuters
El Nino flooding
Houses are seen partially submerged in floodwaters in Asuncion, Paraguay, on 28 December 2015Jorge Adorno/Reuters
El Nino flooding
People try to salvage some of their belongings from the flood in the village of Alberdi, about 130km from Asuncion, Paraguay, on 5 January 2015Norberto Duarte/AFP
El Nino flooding
A woman carries her baby through a flooded area of Concordia, Entre Rios province, Argentina, on 29 December 2015AFP
El Nino flooding
A flooded amusement park is seen in Concordia, Entre Rios province, Argentina, on 29 December 2015AFP
El Nino flooding
An aerial view of a flooded area of Concordia, Entre Rios Province, Argentina, on 2 January 2016AFP
El Nino flooding
Argentina's President Mauricio Macri travels in a helicopter over flooded areas of the city of Concordia on 27 December 2015Argentine Presidency/Reuters
El Nino flooding
Brazil's President Dilma Rousseff looks out of a plane during a flight over the areas hit by floods in Uruguaiana, Brazil, on 26 December 2015Roberto Stuckert Filho/Brazilian Presidency/Reuters
El Nino flooding
People travel on a boat during floods in Paysandú, 380km northwest of the Uruguayan capital of Montevideo, on 26 December 2015Milton Cabrera/AFP

In the US, residents of southern states along the Mississippi River have experienced flooding that also swamped communities from the Ohio River Valley to eastern Oklahoma, causing thousands of evacuations and killing at least 31 people. Flooding in the US Midwest typically occurs in the spring as snowmelt swells rivers.

El Nino flooding
An aerial view from a Missouri National Guard UH-60 Black Hawk helicopter shows the effects of flooding in Pacific, Missouri, on 30 December 2015Missouri National Guard/Reuters
El Nino flooding
Houses in Pacific, Missouri, are surrounded by flood waters on 31 December 2015Michael B Thomas/Getty Images
El Nino flooding
A flooded basement is seen in the home of Emma Smith in Pacific, Missouri on 1 January 2016Kate Munsch/AFP
El Nino flooding
Highway 141 is seen completely submerged in floodwater from the Meremac River in Arnold, Missouri, on 31 December 2015Michael B Thomas/Getty Images
El Nino flooding
A flooded petrol station is seen on Route 141 in Fenton, Missouri, on 30 December 2015Michael B Thomas/Getty Images
El Nino flooding
A home is completely submerged in Fenton, Missouri, on 30 December 2015Michael B Thomas/Getty Images

In the Pacific Northwest and California, the effects of El Niño are only just beginning to be be felt, as they're typically seen in January through March. An El Niño-strengthened storm brought widespread rain to drought-stricken California on Tuesday 5 January, triggering flooding. California is in its fourth year of a drought that has cost the state's agricultural economy $1.84 billion (£1.3bn), according to the University of California, Davis. The El Niño phenomenon is expected to help ease the drought over the next few months, but experts caution that the state's woes are far from over.

El Nino flooding
A driver climbs out of a window of his car after driving onto a flooded road in Van Nuys, California, on 5 January 2016Gene Blevins/Reuters
El Nino flooding
A California Highway Patrol officer gestures at motorists after rocks and debris fell on Malibu Canyon Road following a El-Nino strengthened storm, on 5 January 2016Mario Anzuoni/Reuters

The consequences of El Niño for Europe are not entirely clear. Some forecasters had predicted Britain would be gripped by a severe cold spell this winter. However, December 2015 broke the record for the mildest on record, with temperatures 4.1C above the long-term average. It was also the wettest month since records began in 1910. A number of storms have battered the UK this season, causing severe flooding in Scotland, Wales and parts of England.

York floods
A family are rescued from their flooded home by a mountain rescue team in YorkDarren Staples/Reuters
York floods
A woman cleans the window of Plonkers wine bar in York, as the floodwaters rise on the street outsideJustin Tallis/AFP
York floods
Floodwater rises as the River Calder bursts its banks in the Calder Valley town of MytholmroydChristopher Furlong/Getty Images
cumbria floods
Debris is left on the river bank after the river Greta flooded in KeswickPaul Ellis/AFP
cumbria floods
A car is submerged in flood waters in the city centre of CarlisleAndrew Yates/Reuters
Cumbria floods
Rescue workers pull a boat full of residents along a flooded street in CarlislePhil Noble/Reuters
Cumbria floods
A man stumbles as he wades through flood water in CarlislePhil Noble/Reuters

During the powerful El Niño of 1998, there were freak weather events worldwide that killed an estimated 23,000 people, but the World Meteorological Organisation (WMO) warns that this time round, a combination of the weather phenomenon and global warming may "turn up the heat" in ways never previously experienced.