By Brian Snyder and Brendan O’Brien

MONTPELIER, Vermont (Reuters) -A Vermont reservoir threatened to overwhelm a dam protecting the state’s capital on Tuesday and exacerbate “catastrophic” flooding that has already shut roadways leading out of town and trapped people in their homes.

The Wrightsville Dam, which forms a reservoir four miles (6.4 km) north of Montpelier, was nearing capacity and approaching the point at which a spillway would release water into the North Branch of the Winooski River, city officials said.

That would aggravate what the National Weather Service has called “catastrophic” flooding in Montpelier’s picturesque downtown district, where people navigated the submerged streets in canoes and floodwaters reached the windows of businesses and the tops of vehicles.

The North Branch converges with a second, larger branch of the Winooski near the Vermont statehouse. Downtown flooding was expected until late afternoon, the National Weather Service said.

The growing frequency and intensity of severe weather across the United States is symptomatic of global, human-driven climate change, climate scientists say.

While a Northeast state capital is under water, ocean temperatures have soared to as high as 90 Fahrenheit (32 Celsius) in Florida, Texas is sizzling under a heat dome, and California is bracing for temperatures as high as 120 F (49 C) in desert areas this weekend.

Much of the U.S. Northeast including parts of New York, Massachusetts and Connecticut have already had as much as 8 inches (20 cm) of rain over the last several days.

“Make no mistake, the devastation and flooding we’re experiencing across Vermont is historic and catastrophic,” Vermont Governor Phil Scott said at a briefing Tuesday.

Montpelier City Manager William Fraser in a Facebook post urged the city’s 8,000 people to be prepared to move to the upper floors of their homes as highway closures made evacuations difficult or impossible.

Mayor Jack McCullough told CNN the reservoir level appeared to stabilize about a foot (30 cm) below the overflow status for three hours.

“We take that to be a good sign because it indicates that it’s not getting any worse. On a day like today, not getting any worse is something I will take,” McCullough said.

Throughout the state, search teams have rescued 117 people from their homes and cars by swift boat, as officials fielded calls that even more people were trapped in their homes in remote areas, Mike Cannon, leader of the state’s Urban Search and Rescue operation, told a briefing.

Vermont officials were calling the flooding the worst since Hurricane Irene reached the New England state as a tropical storm in 2011 and caused about $750 million in damages and seven deaths in the state.

The city’s topography – bordered by hills with the downtown in a valley – increases the potential for flooding, Montpelier City Council member Conor Casey said.

“My wife and I live right on the river and it’s about two feet from coming in the living room,” Casey said. “We’re a bit used to it from Irene, so it’s not totally foreign, but I think the scary thing is that it feels a bit worse so far.”

Most of the crops at Boyd Family Farm in Wilmington, Vermont, were lost in the storm, said Janet Boyd, who owns the business along with her husband and son.

The farm, tucked in the southern end of the Green Mountains, has been in operation in the family for 80 years, and Boyd is worried about its future.

“We lost all the vegetables and only have our blueberries left,” Boyd said, “all the greens, the tomatoes, the peppers, the garlic.”

(Reporting by Brendan O’Brien in Chicago and Rich McKay in Atlanta; Additional reporting by Rachel Nostrant and Daniel Trotta; Editing by Devika Syamnath, Bill Berkrot and Sandra Maler)

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