Billion-Dollar Weather and Climate Disasters: FAQ

Below you'll find answers to the questions we get asked most.

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Why use a threshold of $1 billion?
Even though $1B is an arbitrary threshold, these specific events account for the majority (>80%) of the damage from all recorded U.S. weather and climate events (NCEI; Munich Re). In fact, these billion-dollar disaster events are becoming an increasingly larger percentage of the cumulative damage from the full distribution of weather-related events at all scales and loss levels.
Why does billion-dollar disaster tracking begin in 1980?
1980 is the beginning of the first decade in which most all of the public and private sector disaster data resources we use become available.
What about sub-billion dollar disasters after inflation?
Yes, we introduce events into the time series as they "inflate" their way above $1B in costs in today's dollars. Every year, this leads to the introduction of several new events added from earlier in the time series.
Why use CPI to measure inflation?
The Consumer Price Index (CPI) is one of many indices to measure inflation. Other indicies can also be used for comparison, which is why we also provide unadjusted disaster costs.
Are U.S. billion-dollar disasters increasing in frequency and cost?
Yes, the number and cost of disasters are increasing over time due to a combination of increased exposure (i.e., values at risk of possible loss), vulnerability (i.e., where we build; how we build) and that climate change is increasing the frequency of some types of extremes that lead to billion-dollar disasters. More specifically, these trends are further complicated by the fact that much of the growth has taken place in vulnerable areas like coasts and river floodplains. Vulnerability is especially high where building codes are insufficient for reducing damage from extreme events. Climate change is also playing a role in the increasing frequency of some types of extreme weather that lead to billion-dollar disasters - most notably the rise in vulnerability to drought, lengthening wildfire seasons in the Western states, and the potential for extremely heavy rainfall becoming more common in the eastern states.
Has every U.S. state experienced a billion-dollar disaster?
Yes, every state in the country has been impacted by at least one billion-dollar disaster since 1980. Since 1980, there have been more than 100 of these events that have affected at least some part of Texas, while only one event has impacted Hawaii (Hurricane Iniki in 1992). The Central, South, and Southeast regions typically experience a higher frequency of billion-dollar disasters than other regions.
Why are state costs displayed as cost ranges rather than actual values?
Some of the data sources we use include proprietary insurance data, which preclude it from being shared. The cost ranges are a means of providing a comparison of this data without compromising the underlying data.
Has the U.S. experienced more flooding events in recent years?
Yes, the U.S. has experienced an increase in billion-dollar, non-hurricane, inland flood disasters (i.e., from extreme rainfall, riverine flooding) in the last decade (18 floods during 2010-2019) than during the prior 3 decades combined (14 floods during 1980-2009).

Citing this information:

NOAA National Centers for Environmental Information (NCEI) U.S. Billion-Dollar Weather and Climate Disasters (2020). https://www.ncdc.noaa.gov/billions/