Winter has felt more like spring this February, with rising temperatures, a lack of snow and a thunderstorm on campus. Whether you like the warm days or miss winter activities, it’s clear something is causing different weather this year.
This “something” is an El Niño.
What exactly is an El Niño? An El Niño forms when ocean surface temperatures are warmer than usual in the eastern Pacific Ocean. Typically, this means the polar jet stream is further north than its usual place in the south, resulting in abnormally warmer temperatures in the Midwest region of the United States.
This phenomenon was originally recorded by fishermen off the coast of South America. It was named El Niño — “the boy child” in Spanish — because it tends to occur around Christmas.
This isn’t the first year this event has impacted our weather. El Niños usually occur every two to seven years, with the last one in the Midwest occurring eight years ago. It was a powerful El Niño that started in 2014 and lasted through spring of 2016.
This year, temperature records have been broken. On Feb. 8, it was 56℉ in Milwaukee — a city record. In Madison, the University of Wisconsin Police Department posted via Twitter to stay off Lake Mendota due to thin ice. Additionally, Lake Mendota didn’t fully freeze until Jan. 15, its latest freeze date since 2007.
El Niño also affects local wildlife. Many animals rely on snow to hibernate or camouflage themselves. Without snow this year, they may be especially vulnerable to predators.
What will this mean for spring? Although many factors will influence what spring will look like, it’s predicted that El Niño will continue to keep temperatures unusually warm in the Midwest and cooler in the southern parts of the United States.
The Midwest is also predicted to experience an overall drier spring, especially in May. Because the Midwest will be entering spring with drier-than-normal soil, the El Niño will likely hinder recovery from drought.
The El Niño may also impact how many insects are around this summer and when they come out. Warm winter might cause ticks to become active sooner in the year. However, there likely won’t be an increase in the number of ticks or the frequency of Lyme disease because a tick has a long life cycle, requiring two years to become an adult.
Despite these climate concerns, the El Niño may have some benefits. A mild winter can be beneficial for livestock producers because it often reduces animal stress and expenses. Additionally, it can be beneficial to homeowners due to the reduced heating cost that comes with a warmer winter.
Although there are many mixed feelings about our unusual winter, it’s important to understand the science behind it. Whether you’re disappointed at the cancellation of your favorite winter festivity or just happy the sun is out, now you know why it’s so warm and what to expect for spring.
