The number of structures at risk of flooding in the United States could be greater than what was previously thought, according to a study published on Monday.
The study, published on Monday in Earth’s Future magazine, found that 43% of buildings flooded in North Carolina between 1996 and 2020 were located outside the special flood risk area of the Federal Emergency Management Agency, areas that FEM projects have a 1% flood risk in a certain year.
The findings could help more communities be better handled on their flooding and flooding risk needs, experts and authors of the study said. Flood insurance has become increasingly difficult to obtain as some companies increase the price of policies or go back to ensure homes in certain markets due to the most frequent and severe climate. That has left the most vulnerable owners.
Experts told NBC News that with access to correct data sources, databases such as the one described in the study could be developed throughout the country.
Fema maps are the main source nationwide to identify flood -prone areas and what structures should be secured. But experts say the system is outdated and has low resolution. The 100 -year flood projection does not paint a complete image of the areas that probably flood. And climate change has caused previously authorized climatic and climatic projections to be less reliable, the authors said.
The use of data study at the management level allowed researchers to identify specific buildings that had flooded more than once. That information could help the owners know if they should buy flood insurance even outside the fema flood risk areas, experts said. In the United States, 99% of counties have flooded at least once, but only 4% of owners have flood insurance, according to FEMA.
“More information about where it has flooded in the past could help people make different decisions,” said Helena Margaret García, the main author of the study and doctoral student at the University of North Carolina-Chapel Hill.
FEMA and the National Flood Insurance Program did not return comments requests.
Currently, FEMA is in the process of rebuilding its flood mapping system, through an initiative called the future of flood risk data, which says it will provide a more complete look at the risks and risks of flooding in the country using more efficient, precise and consistent technology.
As the planet heats up, the heaviest rain is becoming more common because the hottest air can contain more moisture, which then falls like rain. Climate change is also leading to an increase in world sea level, which has made coastal areas and even inside more vulnerable to floods. Hurricane Helene, the third most dead hurricane in the modern era, caused serious floods in mountainous areas in the middle of North Carolina. The damage totaled more than $ 78 billion, according to the Oceanic and Atmospheric National Administration.
The severe rains have caused sudden floods to cross cities from all over the United States in the last two weeks, more recently on Monday in New Jersey and New York City. Extreme floods resulted in at least six deaths in North Carolina and more than 100 deaths in Texas. Sudden floods are the main murderer related to the storm in the United States, resulting in an average of 125 deaths per year in recent decades, according to the National Meteorological Service
A north Carolina climatologist said that the warmest oceanic waters, which also feed storms, could have been a factor to feed the tropical storm last week, which broke rain and records of rivers in the state.
With the changing climate, having access to updated maps is crucial, experts say.
For the study, the researchers mapped 78 flood events Between 1996 and 2020 using data from the National Flood Insurance Program, the FEMA program through which owners can buy insurance for possible losses related to floods. They also used emergency service and “voluntary geographic information”, which they acquired through public networks publications, to create what they describe as a “first of their type” database. Past flood data are often difficult to access for the general public, which can make it difficult for owners to know if their property has previously flooded, experts said.
Garcia said researchers can use the same study methods to create similar historical maps for regions throughout the country to help officials identify areas in their state that may not have previously thought of as a risk of flooding.
While the study found that only 20,000 of the 90,000 flooded buildings more than once, more than double the number of buildings that presented NFIP claims, the authors of the study are working on research to quantify their human impact. Some analyze the health results, including the way in which a flood could interrupt people’s medical care, and others that investigate the amount of displacement due to repetitive floods, Garcia said.
Antonia Sebastian, assistant professor in the Department of Geological Sciences of UNC-Chapel Hill, said that the study aims to create a “comprehensive registration of past floods” collecting data on flood events that do not reach the largest holders but still have an impact on housing owners.
“The places that have flooded before will be flooded again. It’s just a matter of time,” said Sebastian. “And they are all risky places.”
Chad Berginnis, executive director of the Association of Managers of Plaza de Flood who was not involved in the study, said that FEMA maps are designed to implement the NFIP determining which areas have to buy flood insurance, using the flood plain of 100 years as a guide. He said that the analysis of the study of historical floods emphasizes that officials may need to require flood insurance in areas outside the fema flood risk zone.
“Fema flood maps are a starting point and not an end point,” Berginnis said. “They will show you a type of flood risk, but if you want a total perception of the risk of flooding, one of the things you should do is find historical flood information.”
He said that replicating similar databases models such as the one described in the study in other local areas could help flood administrators to increase consciousness among their communities on who runs the risk of floods by identifying where it has happened previously.
“I just gave the flood history of [the Guadalupe River]And having a daughter of the age who also goes to camps, I mean, this is really hitting me home. You know, how is it that we, that society, are not understanding that these same locations can also be very risky areas and not demand or discover a little more about it? So, I think we clearly have enough awareness of flood risks. “
June Choi, a doctoral student in the science of the land system at Stanford University who was not part of the study, said that the discovery that many flooded buildings were located outside the areas at risk designated by FEMA flood maps is probably the case in all states. The new database can be limited because it does not take into account how the density of the building changes over time. But its use of historical records and specific address data still make it a valuable resource to assess the risk of future floods, he said.
