The Rise in Flooding and Inundation Events

The Rise in Flooding and Inundation Events

The frequency and severity of flood claims and losses is increasing.
Andy Simmons
Andy Simmons, Head of Large Property, The Hartford
Kenneth Travers
Kenneth Travers, Technical Manager - Property Risk Engineering, The Hartford
In August 2021, before Hurricane Ida made landfall in Louisiana, its strength went from a Category 1 storm to a Category 4. As it moved through Louisiana and the U.S., it ripped roofs off homes and buildings, causing flash flooding in areas that historically didn’t have these issues.
Ida caused flash flooding and inundation events in many states. For example, some parts of Connecticut saw nearly 9 inches of rainfall.1 Videos around New York went viral, showing geysers of water shooting out from subway tiles.
It’s estimated that Ida caused between $27 billion and $40 billion in residential and commercial property damage throughout Louisiana, Mississippi and Alabama.2 In the Northeast, a tropical storm-strength Ida caused between $16 billion and $24 billion in damages.3
The trends in the last few years have led professionals at The Hartford to believe natural disasters and storms will continue to be severe and occur more frequently. And because of drainage issues, inundation events can become more common in areas that weren’t typically prone to flooding issues.
These issues are changing how people think of flooding, according to Andy Simmons, head of large property at The Hartford.
“Most of the time, when you think of flood coverage, you think of water rising over a brook or riverbank. But what we’ve seen over the last three or four years, and increasingly last year, is that so much rain comes down in a small period of time, it inundates the sewer system,” Simmons explained. “This leads to surface flooding and flooding where you don’t typically expect it.”
There’s a need to make sure properties and buildings are as safe and protected as possible before a storm or natural disaster hits.
“We’re going to keep seeing these events,” said Simmons. “People used to say you’d see these kinds of storms once every 100 or 200 years, but they’re starting to be one in every 10 or 20 years.”

What’s the Difference Between Flooding and Inundation?

Flooding happens from an overflow of water from a body of water, like a lake or riverbed. This can be due to rainfall. Inundation happens when there’s a large amount of water in an area and it becomes submerged. This can happen if there’s a large amount of rainfall in a short period of time and there isn’t proper drainage. Inundation is also known as pluvial flooding.

How Does Climate Change Affect Storms and Hurricanes?

Rising ocean temperatures can fuel hurricanes – making them more intense and stronger. It’s what happened with Ida as it headed towards Louisiana. Warmer than average water in the Gulf of Mexico added energy and transformed Ida into a Category 4 storm in 24 hours.4
“Ida came in at a Category 4 intensity and it stayed that way as it spent a lot of time sitting over Louisiana. We’re seeing a change in how hurricanes and storms behave,” Simmons explained. “Typically, they get weaker and dissipate as they move north. But that didn’t happen with Ida.”
It’s a trend many scientists believe will continue, where warmer temperatures will result in more severe hurricanes and increased rainfall. In fact, the Intergovernmental Panel on Climate Change found climate change is intensifying the water cycle, bringing more intense rainfall and associated flooding.5

Infrastructure’s Role in Inundation

It’s not just climate change that’s behind inundation and flooding. When there’s a large amount of rainfall in a short period of time, proper drainage is key. If this doesn’t happen, areas and places that don’t typically flood can become submerged, according to Simmons.
The storm sewer system in the U.S. wasn’t developed to move large amounts of water in a short period of time. In fact, the American Society of Civil Engineers gave the country’s stormwater infrastructure a “D” grade when it comes to stormwater.6
Stormwater from rain or snowmelt can travel over impervious surfaces, like roadways or parking lots. It then collects and moves into different bodies of water, such as:
  • Rivers
  • Lakes
  • Bays
  • Oceans
As urban development continues and the amount of impervious surfaces increase, the risk of flooding due to increased runoff from large rainfall events also grows.
While it’s clear that the country’s storm sewer system needs to be updated, the American Society of Civil Engineers found there’s an $8 billion annual funding gap.7
“The local infrastructure in many cases was designed many years ago and urban sprawl has surpassed the original intention and capacity to contain heavy rain or a ‘training’ line of storms moving over the same area continually,” according to Kenneth Travers, technical manager of property and product in Risk Engineering at The Hartford.

An Increase in Flood Claims

Insurers, like The Hartford, have noticed an increase in flood claims. Simmons said it’s not just the frequency, but “the severity is increasing with flood losses.”
The Insurance Information Institute (III) found that there’s typically more damage costs when extreme weather occurs in an area where there’s an increase in:8
  • Population
  • Homes
  • Empresas
  • Infrastructure
Developing land into homes and buildings changes how that property will react to water, Simmons said. Travers added that inundation events will occur more frequently as development increases.
“With continued growth of impervious surfaces, the water is less able to be absorbed into the ground,” Travers explained. “So, it travels and collects and can cause flooding.”

Protecting Business Property From Flooding and Inundation

The majority of businesses buy flood coverage as part of their large business insurance plan, but Simmons said business owners should take measures to protect their property.

Create a Flood Emergency Response Plan

A flood emergency response plan helps business owners prepare for, respond to and recover from a flood. If you don’t have an emergency response plan yet, it’s not too late to develop one.
Emergency response plans should include details about:
  • An evacuation plan with employee responsibilities
  • Sheltering-in-place
  • Medical emergencies
  • Emergency response teams
  • Public emergency services and contractor contact information
The government’s Ready Business website has an emergency response plan template that business owners can use.

Use Flood Walls

Business owners can use temporary mitigation techniques to divert water away from property. For example, businesses can install flood walls around the property to keep it protected from water and even debris.
“A lot of our customers have flood walls they can put in place or have in place in a short amount of time,” Simmons said. “The question is how often do you practice using the flood walls? Make sure it’s not your first time installing flood walls before a storm or hurricane is coming. You want to make sure the walls actually work in protecting your business.”

Building Codes

After Hurricane Andrew, Florida enacted stronger building codes to help ensure buildings and homes can better withstand natural disasters. Professionals at The Hartford believe states along the Atlantic and Gulf coast can change and adopt new building codes to help reduce damages and losses after a storm. In fact, the Insurance Information Institute considers building codes to be “critical to disaster mitigation.”9
Simmons added that conversations around changing building codes is dependent on location. New York, for example, is spending money to make improvements to its infrastructure.
“There’s a recognition that this country has got to do more,” he said.
While changing building codes will take time and effort, professionals at The Hartford said some measures that businesses can take include:
  • Building slightly above grade
  • Using grading to keep water away from structures
  • Moving mechanics and equipment out of the basement
  • Elevating exterior equipment a couple of feet to protect them from inundation

Protecting Against Floods and Inundation Events

It’s not easy to predict how water from a storm or natural disaster will impact businesses, but it’s essential for business owners to take proactive measures to help protect their company and property. In addition to making temporary mitigation efforts, partnering with an experienced insurance company can be beneficial.
At The Hartford, we pride ourselves in knowing the unique risks and challenges that many businesses face. When it comes to flooding and inundation events, we can work with agents and brokers to help business owners better understand how water will behave on their property so we can help prevent issues from happening to yours.”
Learn more about The Hartford’s specialized large business insurance solutions.
1 WTNH, “Governor Lamont Issues State of Emergency Following Flooding Across CT from Ida”
2 CoreLogic, “CoreLogic Estimates $27 Billion to $40 Billion in Insured and Uninsured Losses from Hurricane Ida Wind, Storm Surge and Inland Flooding”
3 CoreLogic, “CoreLogic Estimates $16 Billion to $24 billion in Insured and Uninsured Flood Losses in the Northeast from Tropical Storm Ida”
4 NPR, “How Climate Change Is Fueling Hurricanes Like Ida”
5 Intergovernmental Panel on Climate Change, “Climate Change Widespread, Rapid, and Intensifying”
6,7 American Society of Civil Engineers, “America’s Infrastructure Report Cart 2021”
8,9 Insurance Information Institute, “Facts + Statistics: Flood Insurance”
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