New Report: Extreme Downpours and Snowstorms Up 81 Percent in Massachusetts

Scientists Link Trend to Global Warming

Environment Massachusetts

Boston, MA––Eleven months after Hurricane Irene led to flooding that devastated much of Massachusetts, a new Environment Massachusetts report confirms that extreme rainstorms and snowstorms are happening 81 percent more frequently in Massachusetts since 1948.

“As the old saying goes, when it rains, it pours—especially in recent years as bigger storms have hit Massachusetts more often,” said Sam Feigenbaum, organizer for Environment Massachusetts. “We need to heed scientists’ warnings that this dangerous trend is linked to global warming, and do everything we can to cut carbon pollution today.”

“For centuries New Englanders have dealt with harsh weather, but apparently we hadn’t seen anything yet,” said Representative Ed Markey. “By filling the atmosphere with heat-trapping pollution, we’ve caused the sky to rain down on us in more extreme, damaging ways in the form of stronger, more frequent storms. This report should wash away any remaining doubts that climate change has consequences right now in New England.”

Based on an analysis of state data from the National Climatic Data Center, the new report found that heavy downpours or snowstorms that used to happen once every 12 months on average in Massachusetts now happen every 6.6 months on average. Moreover, the biggest storms are getting bigger. The largest annual storms in Massachusetts now produce 25 percent more precipitation on average than they did 65 years ago.

Scientists have concluded that the rise in the frequency and severity of heavy rainstorms and snowstorms is linked to global warming. Warming increases evaporation and enables the atmosphere to hold more water, providing more fuel for extreme rainstorms and heavy snowstorms.

Feigenbaum pointed to the damage done in Massachusetts by Hurricane Irene in August 2011 as an illustration of what more extreme rainstorms and snowstorms could mean for the state. Hurricane Irene, which dumped up to 9.5 inches of rain on the area, led to over 700,000 homes without power, millions of dollars in damages, and the death of a Southborough man.

State Senator Will Brownsberger noted, “The findings of this report are consistent with what most of us are noticing — the weather seems to be getting more extreme. It’s should be a top long-term priority for coastal and riverine communities to put in place the infrastructure necessary to withstand rising sea levels and more frequent flooding.”

The new Environment Massachusetts Research & Policy Center report, When It Rains, It Pours: Global Warming and the Increase in Extreme Precipitation from 1948 to 2011, examines trends in the frequency of and the total amount of precipitation produced by extreme rain and snow storms across the contiguous United States from 1948 to 2011. Using data from 3,700 weather stations and a methodology originally developed by scientists at the National Climatic Data Center and the Illinois State Water Survey, the report identifies storms with the greatest 24-hour precipitation totals at each weather station, and analyzes when those storms occurred. The report also examines trends in the amount of precipitation produced by the largest annual storm at each weather station.

“This meticulous report is further confirmation that we are living right now with the consequences of global warming,” said State Representative Jon Hecht. “We need to consider carefully how prepared we are to deal with these more severe storms and their aftermath. At the same time, we need to redouble our efforts to cut down on the emissions that are contributing to these disruptive climate changes.”

Nationally, the report found that storms with extreme precipitation increased in frequency by 30 percent across the contiguous United States from 1948 to 2011. Moreover, the largest annual storms produced 10 percent more precipitation, on average. At the state level, 43 states show a significant trend toward more frequent storms with extreme precipitation, while only one state (Oregon) shows a significant decline.

Key findings for Massachusetts and New England include:

  • Extreme rainstorms and snowstorms are becoming more frequent. Massachusetts experienced an 81 percent increase in the frequency of extreme rainstorms and snowstorms from 1948 to 2011. In other words, heavy downpours or snowstorms that happened once every 12 months on average in 1948 now happen every 6.6 months, on average. 
  • Storms with extreme precipitation increased in frequency by 85 percent in New England during the period studied. The New England region ranks 1st nationwide for the largest increase in the frequency of storms with heavy precipitation.
  • The biggest rainstorms and snowstorms are getting bigger. The amount of precipitation released by the largest annual storms in Massachusetts increased by 25 percent.

Feigenbaum was careful to note that an increase in the frequency and severity of extreme rainstorms does not mean more water will be available for human use. Hotter temperatures fuel extreme rainstorms by increasing rates of evaporation. At the same time, however, that evaporation increases soil dryness. Moreover, scientists expect that, as global warming intensifies, longer periods with relatively little precipitation will tend to mark the periods between heavy rainstorms. As a result, droughts are likely to become more frequent and severe in some regions of the United States. Currently, more than half of the lower United States is suffering through prolonged drought, aggravated by the fact that the last six months have been the hottest January-June period on record.

According to the most recent science, the United States must reduce its total global warming emissions by at least 35 percent below 2005 levels by 2020 and by at least 85 percent by 2050 in order to prevent the most devastating consequences of global warming. Environment Massachusetts highlighted two proposals from the Obama administration—carbon pollution and fuel efficiency standards for cars and light trucks through model year 2025, and the first ever carbon pollution standards for new power plants—as critical steps toward meeting these pollution reduction targets.

At the state level, Massachusetts officials are considering ways to improve the Regional Greenhouse Gas Initiative (RGGI), the first-in-the-nation cap on carbon pollution from the power sector that sells permits for carbon emissions and has led to nearly $1 billion in investments in energy efficiency and clean energy solutions in the region.

“How serious this problem gets is largely within our control – but only if we act boldly to reduce the pollution that fuels global warming,” said Feigenbaum. “Massachusetts officials can build on the progress we have made reducing emissions by strengthening the Regional Greenhouse Gas Initiative (RGGI), which has been a key part of our strategy to reduce pollution and shift to clean energy.”