We've heard rumours that El Niño is set to make a return in 2015, which could be great news for ski resorts in North America. With increasing confidence that 2015/16 will see a return of this weather phenomenon, Nick has delved a little deeper into why ski resorts and skiers care about El Niño.
What is El Niño?
El Niño, which means “the boy” in Spanish (as in Jesus – because its effects are most strongly felt in South America around Christmas), is a phase of the El Niño-Southern Oscillation (ENSO) when things heat up over the tropical Pacific Ocean. In a normal year in the tropical Pacific Ocean, trade winds generally drive the surface waters westward. The surface water becomes progressively warmer going westward because of its longer exposure to solar heating. In an El Niño year the easterly trade winds weaken, allowing warmer waters of the western Pacific to migrate eastward and eventually reach the South American Coast. The cool nutrient-rich sea water normally found along the coast of Peru is replaced by warmer water.Why do skiers care about El Niño?
Skiers care about El Niño because a significant change in water temperature across a large area of the Pacific affects weather patterns across the globe. Since the strength of El Niño peaks during late autumn, winter and early spring in the Northern Hemisphere, El Niño’s effects on weather also peak during winter. Effects include:- Increased precipitation across California
- A change in the jet stream across North America, which influences the location of the heaviest snow
- A more southerly storm track in the USA, which often brings higher than average snowfall to the southern third of the U.S. - this frequently means that California, Utah and Colorado can see increased snowfall in El Niño years
- Resorts such as Heavenly, Mammoth and Park City can experience bumper seasons for snowfall in a big El Niño year.