Vermont Reveals the New Dangers of Summer Rain

When a slow-moving storm soaked Vermont with two-months worth of rain on Sunday and Monday, there was a ready comparison at hand: Tropical Storm Irene. The August 2011 storm similarly caused widespread flooding and resulted in more than $700 million in damages. While damage assessments are ongoing from this week’s storm, more than 200 people had to be rescued throughout the state as floodwaters surged, and early images show extensive public and private infrastructure losses.

Governor Phil Scott referred to the recent onslaught as “Irene 4.0” on Tuesday, while the National Weather Service’s Burlington, Vermont, office has repeatedly made its own Irene comparisons to drive home the danger residents continue to face from floodwaters.

However, this was not a tropical storm, which means there’s no name or ranking to refer back to. Instead, it was the sort of no-name summer storm that has long been a feature of the region but is now intensifying due to rising temperatures.

“We're not used to thinking about summer rainstorms as being a really dangerous hazard,” Anna Weber, a senior policy analyst with the Natural Resources Defense Council, told me. “But with the effects of climate change, maybe we should be.”

For many in the Northeast, unpredictable storms are a regular feature of summer months: sheets of rain that slice through the humidity, often ending as abruptly as they began. They might even be welcomed, the accompanying clouds offering a brief reprieve from the baking sun. Such storms are more common from June to September in this area since there is typically more moisture in the air and heat, which can together create atmospheric instability.

The Washington Post described the Vermont storm as a “typical summertime weather system that encountered a powder keg of atmospheric conditions,” including a combination of pressure systems which slowed down the storm’s movement. An official at the National Oceanic and Atmospheric Administration told the Post that the agency’s modeling — based on historical data — would place a storm like this happening in the Northeast at a “1-in-100 chance of occurring in any given year.” But climate change is altering that calculus, with warming conditions correlating with an increase in rainfall quantities.

When it comes to thinking of “really dangerous” storms happening over summer months, it’s probably those tropical systems that come to mind. Gathering over the Atlantic Ocean, they can blow fast enough to be labeled a hurricane before heading for the coast — or, as Irene did in 2011, making their way further inland. But there’s a marked difference in how hurricanes are approached by officials and the public compared to summer storms.

For starters, due to the perceived threat tropical storms pose, they are meticulously tracked from conception to see if they fizzle out or develop into a swirling system worthy of a name. According to the NOAA, the reason you might see your name as a hurricane hashtag over the summer months is “to avoid confusion and streamline communications.” Wildfires receive location-based monikers for a similar reason.

Some researchers have advocated for expanding the label to other disasters, saying they help communicate risk. Last year, Seville, Spain started naming heat waves in hopes of better alerting the public of their risks. Greece is doing it, too. Kostas Lagouvardos, research director at the National Observatory of Athens, told The Observer he believes people are “more prepared to face an upcoming weather event” if it is named.

There is also a set scale in place for hurricanes, though it only takes into account wind speeds, not precipitation. Though it’s an imperfect system, it still offers a way for officials and the public alike to assess the potential risk — something that can be challenging to communicate with no-name storms.

“I would think that if there's a difference between a tropical or summer storm system, it is probably the surprise of people that a summer storm system could actually do something like this,” Chad Berginnis, executive director of the Association of Floodplain Managers, told me.
“Yet the data trends have been very clear now for probably a good decade that we're going to have more intense rainfall events.”

As climate change makes your average summer storm more dangerous, Weber told me researchers are trying to understand how our expectations correlate with protective actions, such as evacuating or stocking up on supplies. It’s a question researchers are posing not only to the public, but also to government agencies and emergency managers, who are tasked with communicating risks to the rest of us and setting relevant protocols in place. The Federal Emergency Management Agency shared its own concern about “conventional natural hazards” in its 2022 National Preparedness Report, explaining that the combination of existing vulnerabilities and hazards intensifying beyond current expectations could be “catastrophic.”

In Vermont, behind many of the comparisons to 2011 was the acknowledgement that the state has dealt with this sort of disaster before. Ultimately, when it comes time to address the damage, Berginnis says the approach is the same whether flooding stems from a hurricane or any other storm. Vermont officials also understood they would likely deal with a bad storm again — the state recently established a Flood Resilient Communities Fund to support locales looking to mitigate flooding damage.

State authorities realized at least two days ahead of the storm they would require additional resources, NPR reported, and they began reaching out to other states for help. On Tuesday, President Biden approved Governor Scott’s request to declare a state of emergency, making Vermont eligible for assistance from the Federal Emergency Management Agency. Both flooding and hurricanes are hazards identified in the Stafford Act, which dictates which natural disasters can receive such federal support. During a press conference Thursday, Governor Scott announced he would also be requesting a major disaster declaration, which, if approved, would unlock additional federal aid once the recovery process begins in earnest.

Unfortunately, Vermont is not there yet: Scattered thunderstorms are forecasted to begin Thursday and last throughout the weekend.