A "warm blob" in the Pacific Ocean could be contributing to the strange weather seen across the U.S. .
The West Coast has been experiencing drought conditions, while the East Coast was barraged with an unusual amount of snow, the University of Washington reported. Fish have also been swimming into new waters, and starving seals have been washing up on shore. Scientists believe the unusual conditions are partially being caused by a patch of water off the West Coast that is between 2 and 7 degrees above normal. The warm patch, dubbed "the blob," is about 1,000 miles in each direction and 300 feet deep.
"In the fall of 2013 and early 2014 we started to notice a big, almost circular mass of water that just didn't cool off as much as it usually did, so by spring of 2014 it was warmer than we had ever seen it for that time of year," said Nick Bond, a climate scientist at the UW-based Joint Institute for the Study of the Atmosphere and Ocean, a joint research center of the UW and the U.S. National Oceanic and Atmospheric Administration.
A recent study worked to get to the bottom of what caused the blob. The researchers found it is linked to a high-pressure ridge that has calmed down the ocean, causing less heat to be lost to cold air. The team also found that these changes are harming marine ecosystems and disrupting the food chain by introducing warm, less nutrient rich ocean water.
The blob can also influence weather on land; when air passes over the warm patch it carries that heat ashore, leading to less snow. This is believed to be a contributor to the drought conditions seen in California, Oregon and Washington. A decadal-scale pattern in the tropical Pacific Ocean was most likely linked to changes in the North Pacific called the North Pacific mode. These changes sent atmospheric waves around the globe, which brought warm air to the West Coast and cold, wet air to the East.
"Lately this mode seems to have emerged as second to the El Niño Southern Oscillation in terms of driving the long-term variability, especially over North America," said Dennis Hartmann, a UW professor of atmospheric sciences.
The researchers noted they did not believe the blob was caused by climate change, but it has many of the same effects on U.S. weather.
"It's an interesting question if that's just natural variability happening or if there's something changing about how the Pacific Ocean decadal variability behaves," Hartmann said. "I don't think we know the answer. Maybe it will go away quickly and we won't talk about it anymore, but if it persists for a third year, then we'll know something really unusual is going on."
