It’s already been a hot summer in New Hampshire. And a climate event could bring more heat and humidity this summer and a wet, warm winter that could put a damper on the ski season and next year’s growing season.
Warm sea surface temperatures along the equator in the tropical Pacific Ocean indicate that the world has entered a naturally occurring climate event known as El Niño, according to climate scientists. They predict this year’s event to reach its strongest classification in what some have dubbed a “super” El Niño.
State climate scientists said the event will likely create warmer, more humid conditions across New England through the rest of the summer and into the fall. Federal forecasters predict the event to intensify heading into the winter months, which scientists said could lead to a warmer winter with less snow and more rain.
Forecasters at the National Oceanic and Atmospheric Administration declared El Niño conditions in June. As of this month, they predict an 81% chance of very strong conditions between October and December, the most powerful El Niño classification.
Forecasters use a very strong designation when surface temperatures are 2 degrees Celsius above the long-term average. The last very strong El Niño occurred from 2015-2016. The federal agency predicts that this El Niño could be one of the strongest on record since 1950.
According to NOAA, the climate event is part of a natural cycle that alternates between periodic warming, cooling — known as La Niña — and neutral Pacific Ocean temperatures that steer global wind and weather patterns.
The El Niño cycle can last 12 to 18 months, according to NOAA, and occurs every two to seven years.
The higher levels of heat and humidity that come with a stronger El Niño will make summer heat waves more intense, said state climatologist Mary Stampone. Very strong winter conditions could harm native vegetation and reduce the amount of water absorbed and stored underground, she added.
What to expect
Cold New England winters kill off invasive plant species and insulate native vegetation from harsh conditions beneath a thick snowpack, Stampone said. The snowpack also replenishes groundwater through a slow melting process that absorbs water into the ground.
Freezing temperatures are still likely, but with more rain than snow in store, Stampone said the rain will run off the frozen ground before the water is absorbed.
“If it’s snow, it sits there and then melts all in during the spring,” Stampone said, “and actually recharges our soil, our groundwater, our surface water systems. Whereas if it’s rain, it just runs right off, goes into the rivers and out to sea. And so that is not good for our hydrology.”
Overall, New Hampshire can expect more volatile and unpredictable weather heading into the winter and next spring, said Dawn Murray, a professor in environmental studies at Antioch University New England.
She said humidity and moisture in the air could relieve some drought conditions in the state. But that could also make for unpredictable short bursts of intense rainfall that could continue into the winter.
“Instead of New England powder, messy kinds of storms,” Murray said.
Scientists are still researching whether or not climate change has made El Niño events more intense, Stampone said. But it’s possible that’s the case, she added, as rising atmospheric temperatures continue to warm global sea surface temperatures.
More heat in the atmosphere adds more energy and moisture to the air that can “supercharge” the natural effects of El Niño, Murray said. She predicts Granite Staters could see more severe heat waves, heavy downpours, and higher humidity during future El Niño events.
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