When it doesn’t rain in a rainforest: Climate scientists study Southeast Alaska drought

Climate scientists are studying the cause and impacts of a three-year drought in Southeast Alaska.
Published: Apr. 19, 2022 at 1:35 PM AKDT
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JUNEAU, Alaska (KTUU) - Southeast Alaska and wet weather are usually synonymous, but the region has known droughts, most recently from 2016 to 2019.

“It’s pretty fascinating to talk to folks about drought in a rainforest, but, indeed, it can happen,” said Andy Hoell, a research meteorologist with the National Oceanic and Atmospheric Administration in Colorado.

This drought was classed as “extreme,” the second most severe type of drought on a scale used by federal agencies and scientists. In 2018, Ketchikan had its “dry year” but still saw over 100 inches of rain.

“That is not what most people would think of when thinking of a drought,” said Rick Thoman, a climate specialist based out of the University of Alaska Fairbanks. “For the region, for the ecosystem, that was way below normal precipitation and it had a significant impact.”

Thoman and a group of climate scientists have studied the drought, its causes and its impacts on Southeast Alaska. Hoell said it was caused, in part, by high pressure systems over the Aleutians, which effectively blocked low pressure systems from circulating across to Southeast Alaska.

The region has recorded droughts in the past, but not as intense as this one. Hoell and Thoman explained that this drought was also notably hotter, leading to more evaporation.

There were significant impacts made by the drought. Thoman says that pests and insects thrived, like the hemlock sawfly, which caused extensive damage. There were reports of water in streams being too warm for salmon to swim up and spawn.

Ketchikan and Juneau generate electricity from hydropower in reservoirs. Those water levels dropped, which can risk communities needing to use diesel.

“The way the society has built up there, and rightly so, is to use all the water that falls from the sky and when you miss out on that water, you have a host of effects,” Hoell said.

Climate scientists are forecasting that over the next few decades, Southeast Alaska will get wetter but also hotter. Thoman says that southern parts of Southeast Alaska may start to resemble the Pacific Northwest with a distinct dry summer season and more precipitation in the cooler months.

Southeast Alaska’s droughts have not really been studied before this ongoing effort. A final report is expected to be ready in 18 months, providing a baseline for scientists to study the region’s future droughts in coming decades.

“They will probably be a little bit more severe,” Hoell said. “Just because of that temperature effect, and having a better feel on that is really, really important.”

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