After a costly dry spell, a wetter outlook

Droughts like the one that cost Vermont farmers nearly $16 million last year might be becoming less common, a new Dartmouth College study suggests, as increased rainfall makes dry spells less frequent and less intense across the Northeast.

But farmers shouldn’t pack up their irrigation equipment just yet.

“What this study does not tell you is that there will not be drought in the Northeast,” said lead author Jonathan Winter. “That is not the case. We have always had drought, and we will continue to have drought.”

The study, published Thursday in the Journal of Hydrometeorology, found that drought in the Northeast has been 59% less frequent and 19% less intense since the mid-1980s compared with the entire period from 1901 to 1983. Winter and his team used more than a century of weather station records to calculate a drought index for the region.

The findings could help Vermont decide how to prepare for drought alongside other weather threats.

Relatively little peer-reviewed research has examined these regional drought trends, which means this study can contribute to a greater understanding of them, Winter said.

Last year’s agricultural losses illustrate how damaging an individual drought can be despite the long-term regional decline. Vermont farmers lost nearly $16 million in drought-related damage last year.

The Vermont Economic Development Authority, which assists businesses affected by disasters, offered loans to those affected. Lawmakers also passed Act 78, establishing a permanent fund for farmers and foresters facing financial losses from weather events.

Supply and demand

The study’s relatively simple drought metric helps describe broad trends, but Vermont State climatologist Lesley-Ann Dupigny-Giroux said drought and its effects are more complicated. She has studied drought and extreme weather in Vermont since the late 1990s.

Drought, in the simplest terms, is a shortage of precipitation. But, its intensity and impact can be affected by many factors, including geography, season, temperature and the type of precipitation.

 “As long as you have a greater demand (on water) than you have supply, you’re in a drought,” she said. “This is exacerbated by how ‘thirsty’ the air or ground is at the time.”

A ‘thirsty’ atmosphere, for example, can evaporate moisture from the ground and worsen drought conditions.

Dupigny-Giroux said new types of drought have emerged in the past decade. These include flash droughts, which intensify quickly, and ecological droughts, the effects of which can actually alter ecosystems.

Vermont was more drought-prone but began getting wetter around the 1970s, Dupigny-Giroux said. That’s about a decade before the shift identified in Winter’s regional research. She attributed Vermont’s change to a combination of factors, including a warmer atmosphere and a shift in storm tracks over the region.

In fact, drought conditions preceded some of Vermont’s worst floods, Dupigny-Giroux said. She pointed to the drought and flood of 1927 and a short period of drought conditions before Irene hit in 2011. There was also a drought in the spring and early summer in 2023 leading up to the historic floods in July, she said.

“By always keeping an eye on history is what allows you to say Vermont is a state that goes from droughts to floods in the blink of an eye,” Dupigny-Giroux said.

The Northeast’s drought decline contrasts with conditions elsewhere in the country. More than half of the U.S. experienced drought conditions this past spring, while the West has endured a prolonged megadrought described in research published in Nature Climate Change as the driest conditions in at least 1,200 years.

Weather disasters strain state and local resources, complicating decisions about which risks to prepare for and how to spend limited funds. Winter said he hopes the findings can help guide those decisions.

“To the extent that we can deploy awareness of, as well as preparedness and adaptation strategies to cope with droughts, these would help move us towards a more resilient place than waiting for droughts to occur and reacting to them,” Dupigny-Giroux said.

Read the story on VTDigger here: After a costly dry spell, a wetter outlook.

Courtesy of VT Digger