In May 2025, Massachusetts had its fifth wettest May on record — a deluge that arrived after six straight months of significant to critical drought across the Connecticut River Valley that fueled wildfires across the state and region.

The state declared the drought over in all but two areas. Relief, it seemed, had arrived.

A year later, that wet May looks less like relief and more like an outlier — one piece of a pattern atmospheric scientists and hydrologists call “weather whiplash,” or wet weather followed by dry weather. A 2026 Dartmouth study found rainfall worldwide has been consolidating into bigger storms and longer dry periods between them over the past few decades, and the Northeast is no exception.

It’s a symptom of a hydrologic cycle thrown out of balance, powered by a warming world.

“It may seem a little counterintuitive that warming can do both of those things,” said Christopher Skinner, an atmospheric scientist at UMass Lowell. “But it’s entirely consistent with the physics of the atmosphere that we’ve known about for more than 100 years.”

Skinner compares the atmosphere to a sponge: it absorbs water as it evaporates and gets “rung out” when it rains. The warmer the air, the more it can hold before it “wrings out.”

However, Skinner says rain requires other atmospheric phenomena to happen. Until those conditions come to squeeze the sponge, the warm weather will keep evaporating the water of streams, rivers and even the soil.

When it finally rains, all that extra water falls at once. The ground often cannot absorb precipitation as easily as smaller, more frequent storms, Skinner said. Often, it runs into water bodies or sewers rather than replenishing underground reservoirs, the less visible but all important stop on the hydrologic cycle.

“It’s not just how much it [rain] falls,” Skinner said. “It’s how it’s delivered, and also then what happens to it, like once it hits the surface, like where does it go.”

The current dry period is still wet compared to 2016, the most recent significant drought. According to the state’s drought plan, Massachusetts’s worst drought took place from 1961 to 1969 when most utilities used emergency supplies. One of the more memorable droughts took place in 1980, when University of Massachusetts sent 11,000 students home after all four water storage tanks dried up.

Droughts are expected to happen more frequently, but not always as multi-year periods. Instead, “flash drought” may occur, the rapid onsets of drought for a much shorter period of time. According to the Massachusetts Drought Management Plan, the state experienced flash droughts in 2016, 2020 and 2022.

“Rapid moving drought is fairly new,” said Vandana Rao, director of water policy at the Massachusetts Executive Office of Energy and Environmental Affairs. “Even if you look at traditional hydrology books, that’s not what drought is defined or written as.”

Different types of drought, however, are not new. Water shortages begin after many months of below-average rainfall, a concept known as meteorological drought. Without any replenishment from the sky, hydrological drought begins as bodies of water and underground reservoirs begin to dry. The lack of water for irrigation eventually slows crop growth and impacts open space, leading to agricultural drought.

Socioeconomic drought, when drought alters the supply of goods, only happens after compounding impacts of water shortages after several months. It could be food supplies, drinking water shortages or even shutting down a college campus.

In our current dry spell, Massachusetts is likely moving out of the meteorological drought. Rain rolled in on July 7 and alleviated dry conditions with 2 inches of rain. But until more water is absorbed into the soil to replenish groundwater, the state’s hydrological drought persists.

“It can be difficult to square the idea that we are getting rainfall but our stream levels are low and groundwater as well,” National Weather Service Meteorologist Andrew Loconto said.

Rao adds that as these whiplash events become more frequent, Massachusetts will need to tweak its emergency response. The Drought Management Task Force she chairs will meet more frequently when these changes happen. If the weather can change so fast, the impacts on people and the landscape will hit just as swiftly.

“If drought is coming in so rapidly, the impacts will also be seen, and so we need to mobilize our assistance and response actions accordingly,” she said.