Billion-dollar weather and climate disasters: overview
The National Centers for Environmental Information (NCEI) is the Nation's Scorekeeper in terms of addressing severe weather and climate events in their historical perspective. As part of its responsibility of monitoring and assessing the climate, NCEI tracks and evaluates climate events in the U.S. and globally that have great economic and societal impacts. NCEI is frequently called upon to provide summaries of global and U.S. temperature and precipitation trends, extremes, and comparisons in their historical perspective. Found here are the weather and climate events that have had the greatest economic impact from 1980 to 2017. The U.S. has sustained 212 weather and climate disasters since 1980 where overall damages/costs reached or exceeded $1 billion (including CPI adjustment to 2017). The total cost of these 212 events exceeds $1.2 trillion.
2017 in Progress…
In 2017 (as of July 7), there have been 9 weather and climate disaster events with losses exceeding $1 billion each across the United States. These events included 2 flooding events, 1 freeze event, and 6 severe storm events. Overall, these events resulted in the deaths of 57 people and had significant economic effects on the areas impacted. The 1980–2016 annual average is 5.5 events (CPI-adjusted); the annual average for the most recent 5 years (2012–2016) is 10.6 events (CPI-adjusted). During the first half of 2017 (January-June), the U.S. experienced a rapid succession of disaster events, which follows the near-record number of billion-dollar disasters that impacted the U.S. in 2016.
From January to June, the U.S. experienced 9 billion-dollar weather and climate disasters, only trailing 2011 and 2016 that had 10 events. The 2017 events included two floods, a freeze, and six severe storms, collectively causing 57 fatalities.
Methodology and data sources
In 2012, NCEI -- then known as National Climatic Data Center (NCDC) -- reviewed its methodology on how it develops Billion-dollar Disasters. NCEI held a workshop with economic experts (May, 2012) and worked with a consulting partner to examine possible inaccuracy and biases in the data sources and methodology used in developing the loss assessments (mid-2013). This ensures more consistency with the numbers NCEI provides on a yearly basis and give more confidence in the year-to-year comparison of information. Another outcome is a published peer-reviewed article "U.S. Billion-dollar Weather and Climate Disasters: Data Sources, Trends, Accuracy and Biases" (Smith and Katz, 2013). This research 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 approximately 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 2016, six of the fifteen billion-dollar events (i.e., the 4 inland flooding events, drought and Hurricane Matthew) have higher potential uncertainty values around the loss estimates due to less coverage of insured assets. The remaining nine events (i.e., 8 severe storm events and wildfire) have lower potential uncertainty surrounding their estimate due to more complete insurance coverage. 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.
In performing these disaster cost assessments these statistics were taken from a wide variety of sources and represent, to the best of our ability, the estimated total costs of these events -- that is, the costs in terms of dollars that would not have been incurred had the event not taken place. Insured and uninsured losses are included in damage estimates. Sources include the National Weather Service, the Federal Emergency Management Agency, U.S. Department of Agriculture, other U.S. government agencies, individual state emergency management agencies, state and regional climate centers, media reports, and insurance industry estimates.