Above Normal Temps Tell The Weather Story Of 2015
With recent memories of freezing temps, snowy passes, high winds, flooding and, maybe even a few popsicle toes, it might take a bit of mental stretching to recall the big weather story of 2015. But there’s no question in KPLU weather expert Cliff Mass’s mind that warmer than normal conditions tell it all.
“The key element last year was above-normal temperatures. The winter was warm; the spring was warm, and the summer was warm,” Mass says.
“Some days were 10 degrees above normal. It was amazing. And we had that huge blob of warm sea-surface temperatures over the north Pacific that added to it.”
Record Low Snowpack
The implications of that warmth were profound, Mass says. First and foremost, its effects on snowpack, which is needed in the Northwest for water supply, far into summer.
“We had near-normal precipitation last year. But we had such warm temperatures that a lot of the precipitation in the mountains fell as rain and not snow,” Mass says.
That means runoff and flooding, instead of natural water storage.
“And so much of the Cascades and the mountains of eastern Washington only got 20 percent of normal snowfall,” Mass says. ”And the Olympics only had about 5 percent.”
It all added up to record-breaking low amounts of snow, Mass says, causing issues for water managers, endangered fish and ski enthusiasts alike.
Although the precipitation levels were normal, allowing normal growth of trees and other fuels, the warmth was so profound that it dried out the surface of soils and vegetation.
“The fuels, the twigs, the grasses - everything dried out,” Mass says. “So during the middle of the summer when we had some lightning coming through, that ignited the forests and the rangelands and we had massive fires.
It was a record year for wildfires, with more than 8 million acres burned before September and dramatic effects on communities such as Chelan, where many homes burned and smoke shut down tourism.
Not Global Warming?
Mass says don’t jump to the conclusion that this is all caused by the greenhouse gas pollution that causes climate change. He says the signal to noise on man-made pollutants versus natural variability is so miniscule that right now it’s not correct to say that this is climate change.
“There’s no reason to think that,”Mass says. “While we were warmer than normal, the eastern United States was cooler than normal.”
He says the warmth here was because of a ridge of high pressure that developed and locked in above us. “And we [scientists] do not think there’s any connection with climate change or global warming.”
The warm temps do give a good window on what the weather will be like in the next century, because of climate change caused by humanity. So climate change is coming; he does not deny that. But Mass says it’s not happening yet.
A Memorable Storm In 2015
Another thing noteworthy about this past year, Mass says, is the earliest windstorm on record, which occurred in late August.
“It was like a winter windstorm, but in August,” Mass says. And it caused massive power outages because the leaves were still on most trees, making them much more vulnerable as the wind swept through them.
“In fact, in British Columbia, more people lost power than for any storm in the past hundred years,” Mass says. He says that storm was one “we’ll remember for ages.”
He says that’s unlikely to happen again anytime soon, because the strong El Nino that has contributed to all the warmth now appears to be fading.
The weekly KPLU feature "Weather with Cliff Mass" airs every Friday at 9 a.m. immediately following BirdNote, and twice on Friday afternoons during All Things Considered. The feature is hosted by KPLU Environment Reporter Bellamy Pailthorp. Cliff Mass is a University of Washington professor of atmospheric sciences, a renowned Seattle weather prognosticator, and a popular weather blogger. You can also subscribe to a podcast of “Weather with Cliff Mass” shows.