This winter has been one of Washington’s warmest and driest on record.
Despite the wet weather we have experienced recently, the state’s snow pack remains much lower than normal. And climate observers say conditions are likely to get worse.
“October through February was the third-warmest start to the water year on record in Washington. And those records are long. They go back to 1895,” said Karin Bumbaco, Washington’s deputy state climatologist.
The warm temperatures have meant precipitation in the mountains is falling as rain rather than snow. Even though more rain has fallen over the past couple weeks, the snowpack is still about 61% of the median.
Meanwhile, Bumbaco said the Climate Prediction Center issued an El Niño watch and a seasonal outlook for May through April. She said it wasn’t good news.
“They're expecting higher chances of above-normal temperatures and below-normal precipitation,” Bumbaco said.“That's even before this El Niño will kick in.”
The “watch” indicates that El Niño conditions could take hold as soon as this summer, meaning even more above-average temps, followed by another dry winter. Washington residents can expect lower streamflows, potential stress on water supplies, an increased risk of wildfires and a longer fire season.
Added to all of this, Bumbaco said, is the influence of marine heat that has persisted off the coast of Washington. It has been about a decade since a major patch of warm water that scientists referred to as “the blob” dissipated. It stuck around for nearly three years. Since then, smaller heat waves have raised water temperatures off the West Coast almost every year. Bumbaco said that extra heat in the ocean transports to the atmosphere above it, often moving inland and boosting temperatures in Western Washington.
The new normal
Research oceanographer Andrew Leising runs the marine heatwave tracker website for NOAA Fisheries, which the agency started after the first blob, which was at that time an extraordinary event. This year, he said, they have been watching a marine heat wave that appeared to be another major anomaly: At one point, it covered a surface area that was even larger than “the blob.” It shifted to a band of warm water right off the coast that persisted until mid-March, at 1 to 2 degrees above normal.
“It actually has backed off a little bit from Washington, so Washington is back to around normal temperatures” Leising said. He said Oregon and northern California saw cooling temps too, thanks to seasonal upwelling of colder water that pushes the heat offshore, starting around San Francisco and northward.
Leising said the heat is still persisting along the coast of southern California, where surfers report more pleasant water temps. But marine heat can lead to harmful algal blooms that make shellfish poisonous, reduce seafood production and can kill marine mammals.
It can also cause atmospheric systems that lock in the heat and can lead to more intense atmospheric rivers and storms.
Leising agreed that the models and current data are all pointing to El Niño arriving by late summer and fall, which will drive more coastal heat through the winter.
“So it will likely be a pretty hot year, and we're very likely to see more records being broken offshore and then again in the near shore next winter,” Leising said.
Both Leising and Bumbaco said they were not surprised to see the recent paper published by the American Geophysical Union, confirming what many have suspected: Global warming is not just continuing at a steady pace, it is accelerating.
The study showed that the past decade ranks as the fastest-warming on record globally. At the current pace, the authors wrote, before 2030 Earth will exceed the limit of 1.5 degrees Celsius of warming set by the Paris Climate Accord.
