Flooding

Climate change is affecting communities nationwide, but Florida often seems like ground zero. In September 2022, Hurricane Ian devastated southwest Florida, killing at least 156 people and causing an estimated US$113 billion in damages. Then Hurricane Idalia shut down the Florida Panhandle in September 2023, augmented by a blue supermoon that also increased tidal flooding in southeast Florida. Communities can adapt to some of these effects, or at least buy time, by taking steps such as upgrading stormwater systems and raising roads and sidewalks. But climate disasters and sea-level rise also harm local governments financially by increasing costs and undercutting their property tax bases. Local reliance on property taxes also can discourage cities from steering development out of flood zones, which is essential for reducing long-term risks. In a newly published study and supporting online StoryMap, we present the first-ever municipal fiscal impact assessment of sea-level rise in...

In August 2023, residents of Juneau, Alaska, watched as the Mendenhall River swelled to historic levels in a matter of hours. The rushing water undercut the riverbank and swallowed whole stands of trees and multiple buildings. The source for the flood was not heavy rainfall – it was a small glacial lake located in a side valley next to the Mendenhall Glacier. Glacier-dammed lakes like this are abundant in Alaska. They form when a side valley loses its ice faster than the main valley, leaving an ice-free basin that can fill with water. These lakes may remain stable for years, but often they reach a tipping point, when high water pressure opens a channel underneath the glacier. The rapid and catastrophic drainage of lake water that follows is called a glacial lake outburst flood, or GLOF for short. The flood waters race downstream over hours or days and often hit unexpectedly. Suicide Basin, a glacier-dammed lake, has flooded the Mendenhall River...

Torrential downpours sent muddy water racing through streets in Libya, Greece and Spain and flooded parts of Hong Kong and New York City in September 2023. Thousands of people died in the city of Derna, Libya. Zagora, Greece, saw a record 30 inches of rain, the equivalent of a year and a half of rain falling in 24 hours. A few weeks earlier, monsoon rains triggered deadly landslides and flooding in the Himalayas that killed dozens of people in India. After severe flooding on almost every continent this year, including mudslides and flooding in California in early 2023 and devastating floods in Vermont and New York in July, it can seem like extreme rainfall is becoming more common. So, what role does global warming play in this? And importantly, what can we do to adapt to this new reality? A powerful storm system in 2023 flooded communities across Vermont and left large parts of the capital, Montpelier, underwater. John Tul...

As questions loom over the Federal Emergency Management Agency’s ability to fund disaster recovery efforts, people whose homes were damaged or destroyed by recent wildfires and storms are trying to make their way through the difficult process of securing financial aid. Residents in communities hit by Hurricane Idalia, the Maui fires or other recent disasters have a long, tough journey ahead. Early estimates suggest Idalia caused US$12 billion to $20 billion in losses, primarily in property damage, acccording to Moody’s Analytics. And rebuilding Lahaina, Hawaii, has been forecast at over $5.5 billion. How well the initial disaster response meets residents’ needs has far-reaching consequences for community resilience, especially for vulnerable residents, as we saw after Hurricanes Katrina and Maria. I am a law professor who focuses on disaster recovery and preparedness and has created several legal clinics to assist survivors. Here’s what anyone facing lo...

Heavy rainfall generated widespread flooding. in the Upper Midwest in late June 2024, putting at least one aging dam at risk. In southern Minnesota, the Blue Earth River cut a path around the Rapidan Dam in Rapidan Township, about 15 miles south of Mankato, on June 24, putting the structure at imminent risk of failing. Officials warned local residents that if the dam burst, the river could rise by 2 feet, but said that evacuations were not needed. This event comes a year after flooding in Vermont collapsed at least one dam and threatened others. Hiba Baroud, associate professor and associate chair in the department of civil and environmental engineering at Vanderbilt University, explains how flooding stresses dams in a changing climate. How serious is the risk when water flows over or around a dam? These conditions can result in erosion, which subsequently could lead to a dam breach or failure and a sudden, uncontrolled release of impounded water. The risk reflects the combin...