Guess Who's Coming to Winter? La Niña or El Niño?

La Niña occurs when the tropical ocean waters near the equator of South America are colder as a result of stronger than normal trade winds pushing the warm water west towards Asia. The cold waters from the deeper parts of the ocean flow upward and the jet stream moves further north than its normal path. When this happens, often the northern areas of the country could see colder temperatures with increased precipitation and snow.

La Niña FAQs

1. La Niña typically peaks during the winter months in North America.
2.  La Niña episodes typically last nine to 12 months, but some prolonged events may last for years.
3.  While their frequency can be quite irregular, El Niño and La Niña events occur on average every two to seven years.
4.  Typically, El Niño occurs more frequently than La Niña.
5.  During a La Niña year, winter temperatures are warmer than normal in the Southeast and cooler than normal in the Northwest.

What does this mean for flooding?

The Midwest may also be at an increased risk of flooding during a La Niña year since it's anticipated to bring about more rain and snowfall in certain parts of the Midwest. Spring river flooding that is all too well-known in this part of the country could become more intense with La Niña.