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Extreme Weather Events – Flooding

Weather Conditions & Terminology |

Extreme Weather Events – Flooding

A flood is simply defined as an overflowing of a large amount of water beyond its normal confines, especially over what is normally dry land. However, floods and their impacts are far from simple. Flood damage can be severe and long-lasting and can be a problem no matter your location in the United States. Every state has experienced at least two major floods in the past 10 years ( Unfortunately, this pervasive issue is also occurring more frequently and more intensely.


Floods are increasing in frequency / intensity

The frequency and intensity of extreme flooding events is on the rise. A warmer atmosphere has resulted in a 7% increase in water vapor floating overhead, which is fuel for developing storms. From 2010 to 2017 NOAA reported 25 separate 500-year flooding events, nationwide. Flooding is now not just a problem for coasts, rivers and streams as inland flooding is now impacting people and businesses in locations where flood insurance was once thought unnecessary.

Increasingly, our floods are becoming more intense as well. In 2021, storms resulting in flooding set all-time worldwide damage records, costing the United States $65 billion, Europe $43 billion, and China $30 billion. These financial losses were caused by significant land instability in Germany and flooded subway systems in New York City and Henan, China, among other things (

“‘The rate of the most extreme rainstorms has increased by a factor of five,’ meteorologist and Weather Underground founder Jeff Masters said. ‘So an event with a 1% chance of happening in any given year — commonly referred to as a “one in 100-year” event — now has a 5% chance of happening,’” he said (


The impacts of a flood

The fact that flood events are occurring more frequently and more intensely is of great concern because floods have several dangerous and damaging consequences. According to Pew Charitable Trust, flood-related events, including hurricanes, severe storms, and downpours accounted for 7 out of 10 presidential disaster declarations in the United States over the last decade.

In fact, flooding is the costliest natural disaster in the United States. It accounted for more than $268 billion in damage in 2017, a number that has risen steadily over the past two decades, and it affects the entire country, including areas well inland (

A recent example of a flood and severe damage occurred in and around Yellowstone National Park mid-June 2022. The floods and mudslides were driven by four days of record rains and melting snow. The floodwaters that raged through Yellowstone changed the course of rivers, tore out bridges, poured through homes, and forced the evacuation of thousands of visitors from the nation’s oldest national park (

The Yellowstone event, like many other flooding events, will have even more impacts than just evacuations and infrastructure damage. Silt and other deposited materials will likely need to be removed to access property and roads in some locations. As we know, there was immediate property damage, but homeowners will also likely have to contend with long-term damage such as dangerous mold growth, as well.

One of the most prevalent consequences of flooding is flood claims. The insurance industry has been impacted by the rise in flood claims. As Homeowners insurance policies usually do not cover flood-related damage, a separate policy from the National Flood Insurance Program is usually required, and premiums have risen – an average of 8% in 2018.

Luckily no one was killed in the Yellowstone flood. The very nature of flash floods makes them fast and very difficult to predict. Since they can occur without warning, it is no surprise that people can be seriously injured or killed by these natural disasters. Also, many flash floods occur at night while people are sleeping adding to the risk (


Current models are dropping the ball on flood prediction

A new Yale-led study suggests that climate models may be drastically underestimating how intense precipitation would become in response to changes in the atmosphere (

Recent years have seen a surge of major storms that have surpassed predictions for precipitation severity. The Yellowstone flooding mentioned previously was one such event. The Yellowstone National Park area’s weather forecast for the morning of June 12 seemed relatively minor: warmer temperatures and rain showers would accelerate mountain snow melt and could produce “minor flooding.” ( No warnings or bulletins were issued mentioning any danger to people.

However, by nightfall, after several inches of rain fell, there were record-shattering floods. Torrents of water poured off the mountains. Swollen rivers carrying boulders and trees smashed through Montana towns over the next several days. The flooding swept away houses, wiped out bridges, and forced the evacuation of more than 10,000 tourists, park employees, and residents near the park (

Climate experts and meteorologists say the gap between the destruction and what was forecasted highlights a dangerous consequence of climate change. Models used to predict storm impacts may not be consistently tracking and predicting increasingly devastating rainstorms, hurricanes, heat waves, and other events (

Hydrologic models used to predict flooding are based on data from historical records. But they do not reflect changes to the climate that emerged over the past decade, said Jeff Masters. “Those models are going to be inadequate to deal with a new climate,” (

“We are literally re-writing our weather history book,” said University of Oklahoma Meteorology Professor Jason Furtado ( The need for changes in the weather modeling approach will have widespread consequences for government and emergency agencies that require weather warnings to determine their disaster response plans. If they’re not warned, they will be unable to properly warn their communities or respond thus potentially being unable to prevent injury or death.

Computer modeling of storms has become more sophisticated and is generally more accurate than ever before. However, extreme weather is volatile and thus hard to forecast, and as severe weather happens more frequently there will be more chances for forecasters to get it wrong (


What To Do Before, During, and After a Flood

For now, these severe weather events are to be expected. There is no way of stopping a storm as it’s happening so the best thing we can do is prepare. Below is a list of things you can do to be prepared and stay safe during a storm gathered from and

  • As for Any Disaster, Have an Emergency Plan & 72-hour Preparedness Kit Ready for Your Family
  • Secure Outside Propane or Other Fuel Tanks
  • If You Suspect a Flash Flood, Immediately Head to Higher Ground
  • During Periods of Intense Rainfall, Listen to Your NOAA Weather Radio, Local Television, or Local Radio
  • Listen for Distant Sounds Like Thunder or a Train, Especially Up Canyons
  • Watch for Rapidly Rising Water
  • Do Not Walk, Swim or Drive Through Flood Waters
  • Stay Off Bridges Over Fast-Moving Water
  • Stay Inside Your Car If Trapped in Rapidly Moving Water – Get on the Roof if Water is Rising Inside the Car
  • Stay Tuned to Broadcasts for Instruction Before, During, & Following the Disaster