It might come as no surprise in Brownville, but heavy rain and snowstorms have been getting worse in Maine for years.

For more than 60 years, actually.

Just a month after a torrent of rain plowed through Brownville and other central Maine towns, the advocacy group Environment Maine released a study Tuesday documenting that “extreme downpours” of rain and snow have been increasing for far more than a half century in Maine. They are hitting the state — and all of New England — far more often.

The study also contends that the dramatic storms will become even more intense and frequent in years to come, resulting in untold human casualties and billions of dollars in property damages.

“When it rains, it pours — especially in recent years as bigger storms have hit Maine more often,” said Ben Seel, clean energy organizer for Environment Maine, who presented the findings of the study. “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.

Environment Maine is a statewide advocacy group working for clean air, clean water and open spaces.

The 43-page study was funded by Frontier Group, an environmental think tank in Santa Barbara, Calif. The report examines trends in severe rain and snow storms from 1948 to 2011 and explains that the storms, known as “extreme downpours,” are fueled by increased evaporation and the ability of a warmer atmosphere to hold more moisture.

The report was based on 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. It 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.

During the last 64 years, New England suffered more often from the increase in these storms than any other part of the country, with an increase of 85 percent in the number of significantly more intense snowfall and rainstorms. In Maine, the storms occurred 74 percent more often that in the mid-20th century.

“And the biggest are getting bigger,” Seel said. Storms are more intense and damaging than before, Seel said, underscoring that flooding causes “the greatest damage in the U.S. — more than any other (type of) natural disaster.”

The report represents one of the more recent warnings by environmental organizations about global warming, linking the trend toward increased temperatures (about 2 degrees Fahrenheit in the last half century) to a host of problems, including drought, worsening pollution, poor crop yields, higher food prices and threats to human health.

Environment Maine estimated losses from extreme storms in 2011 to be as much as $8 billion in damage to property and crops in the U.S. Floods alone resulted in 100 deaths that year. Farmers, attempting to adjust to the climactic patterns, lost at least $3 billion a year during the latter half of the 20th century because of extreme weather.

No one has escaped the damage and strain of these storm trends. New England has experienced the phenomenon to a greater degree, in part because it lies in the path of several major storm fronts in the U.S. The rest of the country has been buffeted, too, by increases in intense storms that occur more often.

In Portland, wastewater systems have been strained by the increased storm runoff from intense storms, and to deal with the excess water, the city during some particularly heavy rainfall has emptied sewer lines, discharging raw sewage along with storm runoff. It is expected that it will cost about $170 million to upgrade the wastewater system in Portland alone, over and above the $94 million already allocated and largely spent on resolving the issue.

When storm runoff — including eroded soil and pesticides — is discharged with raw sewage, the flow goes directly into streams, rivers, lakes and the ocean, degrading water quality along beaches and in many coastal and inland-lake communities. Portland is not alone in struggling with the problem; it occurs in hundreds of communities around the country.

“There’s no question that … weather patterns are changing,” said U.S. Rep. Chellie Pingree, D-1st District. “It’s time we woke up and did something about it.”

Climate change “is not good for agricultural production,” she said, adding that the fallout from devastated harvests “will lead to higher food prices … and food insecurity” for the nation.

State Sen. Justin Alfond said the report delivered “clear evidence” of global warming and its effect on various sectors of the economy. “Maine cannot go backward” in confronting the issue, he said. He praised the Regional Greenhouse Gas Initiative, a pioneering program that strives to limit carbon pollution from the power sector, and said efforts to limit pollution must continue.

Calling the controversy about climate change and measures to fight it “a continual fight” among U.S. lawmakers, Pingree underscored the need for support for “green energy” alternatives to oil.

The report urged local, state and federal officials to help communities “rapidly and substantially reduce pollution that causes global warming.” Seel also said the group advocates that all levels of government plan to budget increases in disaster-relief funding.

Public officials at every level should “take steps to better protect the public ” rather than let residents “suffer the full brunt of these extreme events,” the report said.

That recommendation probably hit home in Brownville, which was almost completely cut off from the rest of the state on June 23, when a flash flood washed out roads, killing on impact one driver who stuck a large piece of pavement on a washed-out section. The storm led to hundreds of thousands of dollars in damages in Brownville and caused numerous town roads to erupt from the force of the water into a jigsaw-puzzle of pavement pieces. Eight inches of rain fell in the area in three hours.

Brownville, however, has been declared ineligible for money from the Federal Emergency Management Agency to help pay for storm damages. The agency requires that damages amount to $1.8 million before a community can receive federal emergency disaster relief and Maine Emergency Management officials.

At the request of Gov. Paul LePage, FEMA staff conducted a survey of the damage in the area near the towns of Brownville, Milo and Patten. Their estimate came in a bit under $700,000.