Famous for its tornadoes, Oklahoma is no stranger to other forms of severe weather like flooding and snowstorms. A naturally occurring phenomenon called El Niño could escalate some of those systems in the coming months.
The climate pattern forms when winds over the Pacific change and warm water is pushed east toward the west coast of the Americas. It’s part of the El Niño-Southern Oscillation cycle, which includes its counterpart, La Niña. The National Oceanic and Atmospheric Administration estimates it occurs every two to seven years.
For months, climatologists have warned of an incoming El Niño of historic strength. As of early November, NOAA scientists predict the planet has at least an 83% chance of seeing this one exceed all other recorded El Niño events. Official reports date back to the 1950s.
In Oklahoma, the climate event typically brings colder-than-normal temperatures and increased precipitation. Whether the state experiences more snow than usual or the season is defined by rain remains to be seen.
Jason Furtado, professor of meteorology at the University of Oklahoma, said the region is already seeing some of El Niño’s influence.
“El Niño is here — it's happening — whether it's going to be strong or very strong is sort of where that percentage is right now,” Furtado said of NOAA’s forecast. “But all consensus right now is that we are in for an extremely strong, very significant El Niño this year.”
In October, parts of Oklahoma saw record-breaking rainfall after months of intense heat. The Oklahoma Mesonet recorded a statewide rainfall average of 4.42 inches, slightly higher than normal. Still, the organization found the combined months of September and October were the warmest on record.
State Climatologist Gary McManus said the prolonged heat may prevent winter averages from dipping below normal during El Niño because it’s starting higher than usual.
“But it just takes one storm to have what's considered a bad winter,” McManus said. “It can be a bad blizzard or a bad ice storm, just a really big winter storm with lots of snow and sleet and freezing rain all mixed together.”
“We could go the whole winter with just cold rain. It just depends on what we have as the ingredients for each storm.”
McManus said he still expects periods of cold and freezing temperatures in the coming months. Long-term averages predicted by NOAA and other forecasters won’t include day-to-day weather variability.
“What happens during those extended periods of cold weather? Is it high and dry, lots of sunshine, or will there be a series of storm systems? It's really still all possible as we look forward,” he said.
Strong El Niños have occurred in the past, most recently between 2015 and 2016. Heavy rainfall and some snow broke a multi-year drought during that period. The 1982 to 1983 El Niño was also among the strongest at the time, matching increased precipitation in parts of the state.
Another consideration among scientists is the relationship between El Niño, which is natural and temporary, and climate change. As the planet warms, primarily driven by human activities like burning fossil fuels, more heat and moisture in the atmosphere can fuel extreme weather.
“Winters today are much warmer than they were in the early 1980s,” Furtado said. “So, we have an El Niño raging and forming. But it's forming in a world that is much warmer overall, much stormier. And so that is really important.”
“We're injecting something that's super strong into sort of a really, literally, juiced-up warmer climate system.”
More research is needed on the relationship, but a recent study published in the journal Science suggests there could be evidence of climate change strengthening El Niño events.
How is Oklahoma preparing for El Niño?
Mack Vest is stepping down in early November and will be replaced by Chief Operations Officer John Dean in the interim.
“For me, it perks my ears up, but until we get closer to any sort of weather system coming into the state, it's really hard for us to plan,” she said. “A few weeks out, we might see that a pattern's coming in, and by the time it gets within 72 hours, or 48 hours, or 24, it's shifted somewhere entirely else.”
The department supports coordination among other state agencies and at the local level during emergencies. Still, Mack Vest said the department will likely monitor flooding impacts in the spring if the state becomes saturated with rain during the fall and winter.
“I really just think it's situational, but it certainly evolves over the course of months and weeks,” she said.
Preparing at home is key to staying safe during severe weather like flooding, Mack Vest said. That could include checking floodplain maps, keeping a weather radio and making an emergency plan for families and pets.
As of October, NOAA predicts an average increase in precipitation in Oklahoma. Some of the state could see above-normal temperatures.
But State Climatologist Gary McManus warns against placing bets on specific weather conditions. El Niño tilts the odds toward cooler and wetter weather, but it’s not guaranteed.
“This gives us a more variable weather possibility. But again, Oklahoma weather almost never disappoints,” he said.
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