Rethinking the “100 Year Flood” in Vermont

On Monday, July 10, Vermont experienced such intense rainfall across the state that rivers crested their banks and ran rampant over the landscape. Some parts of the state experienced up to two months of rain in less than 24 hours with minimal warning  (Rathke, 2023). I live in central Vermont in Waterbury, consisting of approximately 1800 residents and a popular spot for summer and winter enthusiasts. Our downtown abuts the Winooski River, which flooded the entire historic downtown business district for the second time since 2011 during Hurricane Irene. The last major flood in our town before Hurricane Irene was the Great Flood of 1927, when rivers reached 13 feet or more above their typical depth, demonstrating the lapse between these catastrophic flood events has diminished significantly.

The Tuesday following the immense rain on July 10 was chaotic. Downtown homes and businesses dealt with muddy river water filling their basements and rising to the first floor. Residents were transporting themselves around neighborhood streets via canoes and kayaks. Cornfields and recreational sports fields became part of the river. What should have been a pleasant summer week in Vermont was a catastrophe. By Wednesday, the water had mostly receded. Now came the cleanup. Volunteers showed up to help pump out basements and remove mud. People begin to assess damage to their homes and businesses. The flooding in Waterbury impacted about 15 companies and more than 150 properties. Across the state, the impact of the storm was even worse. President Biden approved an emergency declaration for Vermont. Our capital city of Montpelier completely flooded, the worst since 1927, as the Winooski River at Montpelier reached close to 21 feet, with tens of millions in damage caused by the event (Ganley, 2023). Across our agricultural state, farms and crops had a devastating impact.

According to Vermont Governor Phil Scott, “In our mountainous state, much of our most fertile farmland lies in river valleys, and countless fields of corn, hay, vegetables, fruit, and pasture were swamped and buried.”  (Vermont Starts Long Road to Recovery from Historic Floods Helped by Army of Volunteers, 2015)

As I live at 1000 feet elevation, my house only experienced minor flooding in the basement from the heavy rains. Still, to our community, it was devastating and a stark reminder of August 28, 2011, when the remains of Hurricane Irene hit Vermont as a tropical storm, dumping up to 7 inches of rain in less than 24 hours. It was the worst weather disaster to strike Vermont since the November 3-4, 1927, flood, the greatest natural disaster in Vermont’s history. Devastation occurred throughout the state, with 1,285 bridges lost, countless homes and buildings destroyed, and hundreds of miles of roads and railroad tracks swept away. (Vermont Starts Long Road to Recovery from Historic Floods Helped by Army of Volunteers, 2015) Today, historic signs on century-old downtown buildings in Waterbury show the impact of the 1927 flood. Those markers stand over eight feet high. It’s odd to need to turn your head up on a building to see how high the flood water stood. Vermonters used to call these events the “100-year flood,” which is a flood event that has, on average, a 1 in 100 chance (1% probability) of being equaled or exceeded in any given year.  (100 Year Flood, n.d.) But can no longer.

According to the New York Times, catastrophic flooding can increasingly happen anywhere without warning. And the United States, experts warn, is far from ready for that threat.  (Rojas, 2023) As the Flood of 1927 in Vermont shows, significant river flooding is not new. It is rising temperatures that enhance the problem. Global warming from climate change means more evaporation and more atmospheric moisture, causing rain to intensify. Every 1-degree Fahrenheit rise in temperature can represent 4% more water vapor in the air. And since the average surface temperature was more than 2 degrees Fahrenheit warmer in 2020 than a hundred years ago, there can be nearly 9% more moisture in the air — and clouds. These rising temperatures allow the air to hold more water, leading to more intense and sudden rainfall, called “flash floods,” seemingly out of nowhere.   (Why Are Floods Hitting More Places and People , n.d.). And the consequences of that shift are massive.

“It’s getting harder and harder to adapt to these changing conditions,” said Rachel Cleetus, policy director for the climate and energy program at the Union of Concerned Scientists. “It’s just everywhere, all the time.”  (Rojas, 2023)

Nationally, as seas rise and storms get worse, the most flood-prone parts of the country — cities such as Miami, New Orleans, Charleston, and Houston, and parts of New York City have resulted in the federal government increasing funding toward climate resilience projects.  (Rojas, 2023)The 2021 infrastructure bill allocated approximately $50 billion for these projects and is American history’s most significant infusion toward climate resilience projects. But the funding is still far below what is required. This past spring, the Federal Emergency Management Agency (FEMA) said it had received $5.6 billion in applications for two of its main disaster-preparedness programs, nearly twice as much as was available.  (Rojas, 2023)

In Waterbury, following the storm, I observed FEMA signs posted and their trucks around the flood zone of our town. But in Johnson, Vermont, 26 miles away, a resident with a home damaged from 5 feet of water in her living room, and no flood insurance, posted a large sign in her yard stating, “WE NEED HELP FEMA!” with her phone number below. The resident said she hadn’t yet seen FEMA in Johnson. (Giles, 2023)

Anna Weber, a senior policy analyst at the Natural Resources Defense Council who specializes in flood risks, said the government needs to direct more money to the most economically vulnerable communities — those places that are least able to pay for resilience projects on their own.  (Rojas, 2023)

Today in Vermont, we are bracing for months of flood cleanup and recovery across the state. The reality that rebuilding Vermont will take months instead of weeks is sinking in. Residents are now wondering if a new normal with climate change means they should rebuild their homes and businesses higher. Vermont’s fall foliage draws plenty of tourists; local restaurants and shops hope to recover by then, as do residents in the flood zones renovating their damaged homes.  (Vermont Braces for Months of Flood Clean Up and Recovery, 2023) But as Hurricane Irene in 2011 left Vermont residents thinking climate change may cause these catastrophic floods to occur more often, the evolution of 100-year floods to a dozen years (between Hurricane Irene and the July 10 storm) has left everyone in our state rethinking their timelines on the gaps between these events.

By Jarett Emert