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 2018, there were 14 separate billion-dollar weather and climate disaster events across the United States, with a total cost of $91 billion. The total cost over the last 3 years (2016-2018) exceeds $450 billion — averaging $150 billion / year. The total cost over the last 5 years (2014-2018) is approximately $500 billion — averaging $100 billion / year, as indicated by the black line below.
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 from extreme weather.
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 2018, three of the fourteen separate billion-dollar events (i.e., hurricanes Florence and Michael, and the Western drought) have higher potential uncertainty values around the loss estimates due to less coverage of insured assets and data latency. The remaining eleven events (i.e., the 8 severe storm events, 2 winter storms and California wildfires) 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 2019, NCEI added three historic weather events, which now surpass $1 billion in inflation-adjusted costs. These events include:
- Western, Central and Northeast Severe Weather - January 2008: Strong storm produces severe weather including hail, high winds and heavy precipitation from California to New York. Flash floods and landslides cause damage in California. In addition, more than 70 tornadoes were reported from Arkansas to Wisconsin, with the highest concentration of tornadoes in Missouri.
- Southeast Winter Storm - January 2000: Strong winter storm causes disruption and damage over numerous southeastern states (AL, GA, NC, SC, TN, LA, VA). Record amounts of snowfall occured across central North Carolina, with snow totals in excess of 20 inches.
- Northern Plains and Ohio Valley Severe Weather - July 1993: Severe storms caused high wind, hail and tornado damage across many Northern/Central Plains (NE, KS, MO, IA, MN, ND) and Ohio Valley states (IL, IN).
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 (2019). https://www.ncdc.noaa.gov/billions/