Billion-Dollar Weather and Climate Disasters: Time Series
The graphic below helps to visualize how the different types of identified U.S. Billion-dollar disaster events have changed over time. Caution should be used in interpreting any trends based on this graphic for a variety of reasons. For example, inflation has affected our ability to compare costs over time. To reflect this, the graphic also shows events with less than $1 billion in damage at the time of the event, but after adjusting for Consumer Price Index (inflation), now exceed $1 billion in damages.
In 2017, there were 16 weather and climate disaster events with losses exceeding $1 billion each across the United States. More notable than the high frequency of these events was the cumulative cost, which exceeded $300 billion in 2017 — a new U.S. annual record.
Milestones to Improve Data Analysis
In May 2012, NOAA's National Centers for Environmental Information -- then known as National Climatic Data Center (NCDC) -- hosted a workshop including academic, federal, and private sector experts to discuss best practices in evaluating disaster costs.
A research article "U.S. Billion-dollar Weather and Climate Disasters: Data Sources, Trends, Accuracy and Biases" (Smith and Katz, 2013) regarding the loss data we use, our methods and any potential bias was published in 2013. This research article found the net effect of all biases appears to be an underestimation of average loss. In particular, it is shown that the factor approach can result in an underestimation of average loss of roughly 10–15%. This bias was corrected during a reanalysis of the loss data to reflect new loss totals.
It is also known that the uncertainty of loss estimates differ by disaster event type reflecting the quality and completeness of the data sources used in our loss estimation. In 2017, seven of the sixteen billion-dollar events (i.e., the 2 inland flooding events, drought, freeze and hurricanes Harvey, Irma and Maria) have higher potential uncertainty values around the loss estimates due to less coverage of insured assets and data latency. The remaining nine events (i.e., the 8 severe storm events and wildfire) have lower potential uncertainty surrounding their estimate due to more complete insurance coverage and data availability. Our newest research defines the cost uncertainty using confidence intervals as discussed in the peer-reviewed article "Quantifying Uncertainty and Variable Sensitivity within the U.S. Billion-dollar Weather and Climate Disaster Cost Estimates" (Smith and Matthews, 2015). This research is a next step to enhance the value and usability of estimated disaster costs given data limitations and inherent complexities.
The most recent analysis offers new graphing options to better visualize event costs over time. These options include: 1) annual U.S. disaster costs for billion-dollar events including 95% confidence interval estimates of cost uncertainty and 2) the 5-year cost mean. The 95% confidence interval (CI) probability is a representation of the uncertainty associated with the disaster cost estimates. Monte Carlo simulations were used to produce the upper and lower bounds (Smith and Matthews, 2015).
In April 2018, we added eight historic events, which now surpass $1 billion in CPI-adjusted costs.
These events include:
- Southeast Severe Weather - November 1992: Three-day tornado outbreak strikes many Central and Eastern states including TX, LA, AL, MS, GA, AR, IN, OH, KY, TN, and NC. Major damage was reported across many areas, as more than 100 tornadoes were reported. This event remains one of the most prolific Fall season tornado outbreaks on record. Total Estimated Costs: ($1.2) Billion*; 26 Deaths
- Southeast Severe Weather - March 2005: Severe storms cause widespread hail damage across numerous states including TX, AL, MS, GA, FL, NC and VA. Total Estimated Costs: ($1.1) Billion*; 0 Deaths
- Central Severe Weather - October 2006: Severe storms cause high wind and hail damage across numerous states including OH, IL, IN, MI, MN and WI. Total Estimated Costs: ($1.1) Billion*; 1 Death
- Rockies/Central/East Severe Weather - June 2010: Severe storms cause high wind and hail damage across numerous states including CO, NM, KS, OK, IL, IN, GA, SC and NC. Total Estimated Costs: ($1.0) Billion*; 2 Deaths
- Tropical Storm Frances - September 1998: Tropical Storm Frances caused extensive flooding in Texas and Louisiana. The rainfall totals from Frances were 10 to 20 inches across eastern Texas into southern Louisiana. Total Estimated Costs: ($1.1) Billion*; 2 Deaths
- Hurricane Erin - August 1995: Hurricane Erin impacted Florida as a category 1 hurricane. Most of the damage resulted from heavy rainfall and flooding in Florida, Alabama and Mississippi. Total Estimated Costs: ($1.4) Billion*; 6 Deaths
- Florida Freeze - January 1981: Severe freeze heavily damaged fruit crops across Florida. Over 25,000 Florida farms were impacted and sustained losses. Total Estimated Costs: ($1.6) Billion*; 0 Deaths
- South Florida Flooding - October 2000: Heavy rainfall up to 15 inches affected south Florida surrounding Miami that resulted in severe flooding that damaged thousands of homes and businesses. There was also several hundred million in damage done to agriculture. Total Estimated Costs: ($1.3) Billion*; 3 Deaths
*Exceeds $1 billion-dollar threshold after 2018 Consumer Price Index adjustment
For more information, please see: Calculating the Cost of Weather and Climate Disasters.
Citing this information:
NOAA National Centers for Environmental Information (NCEI) U.S. Billion-Dollar Weather and Climate Disasters (2018). https://www.ncdc.noaa.gov/billions/