North Pole Environmental Laboratory
Wild weather events are a fact of life. But 2015 distinguished itself in at least one major way: overall, it was the hottest year on record. Along with a strong El Niño pattern, which tends to bring bizarre and extreme weather events, extra warmth in the atmosphere set off a cascade of record-setting weather phenomena -- from massive snowstorms to an oddly calm hurricane season in the Atlantic.
This week, according to some predictions, temperatures at the North Pole will rise 50 degrees or more above normal, toppling the freezing point for only the second time ever in recorded history. Meanwhile, a hurricane-force storm, named Frank, is moving into the United Kingdom, carrying 120 mph winds and torrential rainfall.
“Every year has extreme stuff that goes on,” says Jeff Weber, an atmospheric scientist at the University Corporation for Atmospheric Research in Boulder, Colo. “But 2015 was a highly unusual year.”
A man skis across an intersection during a winter snow storm in Brookline, Mass., on Feb. 9, 2015. BRIAN SNYDER/Reuters/Corbis
As the end of 2014 turned into the beginning of 2015, winter slammed Boston with the snowiest season ever recorded, eventually totaling more than 110 inches -- or more than 9 feet.
The reason likely had its roots in a warmer climate -- and it wasn’t just this year. The warmest year on record was 2014 until 2015 came along. Warmer air can hold more moisture that, in turn, produces wetter storms. The winter may have felt endlessly chilly to Boston residents. But it was warmer temperatures in the middle and upper layers of the atmosphere, Weber says, that made the season so white.
The month of March usually marks the beginning of severe weather season throughout the United States, particularly in the Central and Southern Plains. This year, despite the rough Northeastern winter that preceded it, not a single severe storm occurred in the United States between March 1 and March 24, Weber says. The last week of the month was relatively calm, too.
Overall, meanwhile, this year marked a near-record scarcity of powerful storms in the Atlantic (a pattern that was balanced by a record high number of hurricanes and cyclones in the Pacific). The strangely quiet Atlantic was probably a function of El Niño, which increases winds and disrupts the formation of tropical storm systems there. “It literally shreds them before they can really spin up and get going,” says Paul Douglas, senior meteorologist and founder of AerisWeather. “It was a supernaturally quiet hurricane year in the Atlantic.”
A Coast Guard overflight shows the effects of flooding in the South Carolina counties of Berkley and Williamsburg. U.S. Coast Guard/Petty Officer 1st Class Stephen Lehmann.
After the wettest May ever in Oklahoma and an extremely wet spring in Texas, the region fell into a flash drought. From August to October, very little rain fell. Along with hot temperatures, crops suffered and fires burned. But when precipitation started up again, it hit hard. Extreme floods were reported across Oklahoma, Texas, South Carolina and Florida in October.
Despite experiencing six months this year with below-average rainfall, the South ended up having it’s wettest year ever. “It’s been a topsy-turvy season for the Red River Valley,” Weber says. “It’s been a very, very roller-coaster year.”
Typhoon Kilo, Tropical Storm Ignacio, and Hurricane Jimena in the Pacific Ocean are captured by Japan's Himawari satellite on Sept. 2. JMA/NOAA
In late August, for the first time in recorded history, Weber says, three super-strong hurricanes formed in the eastern Pacific -- all at the same. Named Kilo, Ignacio and Jimena, all three storms reached Category 4 status, with winds exceeding 130 miles per hour.
Hurricanes feed off warm surface waters in the ocean, which explains why the hurricane season normally peaks in late summer. But, when one strong hurricane sweeps through, it usually churns up the ocean so much that cold waters rise from below, squelching the potential for more storms to form right away. This year’s hurricane trifecta, Weber says, “signals to us not only that the surface waters are warm, but that the warm temperatures go to great depths.”
As hurricane Patricia formed in mid-October in the eastern Pacific, it intensified with remarkable speed, rapidly becoming the strongest hurricane on record. Winds reached a previously unheard-of 200 mph. Meteorologists also marveled a central pressure of 879 millibars -- the lowest ever recorded for a hurricane in the Western hemisphere.
Concern escalated as Patricia approached Mexico, and flooding ended up causing billions of dollars of damage. But it could have been much worse. Patricia rapidly dissipated upon landfall, sparing affected areas from utter devastation.
The first tropical cyclone ever known to hit Yemen arrived in early November, fueled by extra-warm water in the Arabian Sea. At its peak, Cyclone Chapala reached Category 4 intensity. By the time it hit land, it had weakened somewhat, but was still a roaring Category 1 storm, with winds gusting to 75 mph.
Political unrest in Yemen makes it hard to get much information out of the region, Weber says. But the storm likely brought “at least five years’ worth of rain” to a normally dry area, reported the Washington Post’s Capital Weather Gang. Strong waves and floods were potentially catastrophic.
Record hot temperatures were widespread this year. Parts of Alaska saw temperatures that exceeded 90 degrees in May. East of the Cascades, parts of Oregon, Washington State and Idaho set June temperature records that soared as high as 116, according to Weather Underground. Wildfires in Alaska and western Canada produced smoke that traveled all the way to Washington, D.C., Douglas says, adding that simultaneous summer heat waves struck four continents at once. The list of places reporting record highs and extra-long stretches of heat this year included India, Egypt, Germany, Poland, Spain, the United Kingdom, and South Africa.
Mid-December brought the deepest low pressure ever recorded in an extra-tropical cyclone in the Gulf of Alaska, Weber says. Sustained winds in the Aleutian Islands exceeded 100 mph for hours. Weber suspects that the system could alter the jet stream, triggering unusual weather in the rest of the country over the coming weeks. “I think,” he says, “we’re about to get some very interesting weather coming through.”