U.S. Billion-dollar Weather and Climate Disasters of 2017 - in Context

NOAA’s National Centers for Environmental Information (NCEI) tracks U.S. weather and climate events that have great economic and societal impacts (www.ncdc.noaa.gov/billions). Since 1980, the U.S. has sustained 219 weather and climate disasters where the overall damage costs reached or exceeded $1 billion (including adjustments based on the Consumer Price Index, as of December 2017). The cumulative cost for these 219 events exceed $1.5 trillion.

During 2017, the U.S. experienced a historic year of weather and climate disasters. In total, the U.S. was impacted by 16 separate billion-dollar disaster events including: three tropical cyclones, eight severe storms, two inland floods, a crop freeze, drought and wildfire.

2017 ties 2011 for the highest number of billion-dollar disasters for a single year. 2017 arguably has more events than 2011 given that our analysis traditionally counts all U.S. billion-dollar wildfires, as regional-scale, seasonal events, not as multiple isolated events.

More notably than the high frequency of these events is the cumulative cost, which exceeds $300 billion in 2017 - a new U.S. annual record (NOAA 2017). The cumulative damage of these events is $306.2 billion, which shattered the previous U.S. annual record cost of $214.8 billion (CPI-adjusted) in 2005 due to the impacts of Hurricanes Dennis, Katrina, Rita and Wilma. The damage from Hurricanes Harvey, Irma and Maria alone are responsible for approximately $265.0 billion of the $306.2 billion. Each of these destructive hurricanes now joins Katrina and Sandy, in the new top 5 costliest U.S. hurricanes on record.

This graphic depicts the accumulation in the estimated cost of billion dollar weather and climate disasters on a monthly basis, for each year since 1980.

Distribution of costs and fatalities by disaster type

The distribution of damage from U.S. Billion-dollar disaster events from 1980 to 2017 (as of January 8, 2018) is dominated by tropical cyclone losses. Tropical cyclones have caused the most damage ($850.5 billion, CPI-adjusted) and also have the highest average event cost ($22.4 billion per event, CPI-adjusted). Hurricanes are responsible for slightly more than half (55.3%) of the total losses for all the U.S. billion-dollar disasters but represent less than one-fifth (17.4%) of all the billion-dollar events we have assessed since 1980.

Drought ($236.6 billion, CPI-adjusted), severe storms ($206.1 billion, CPI-adjusted) and inland flooding ($119.9 billion, CPI-adjusted) have also caused considerable damage based on the list of billion-dollar events. Severe storms have caused the highest number of billion-dollar disaster events (91), while the average event cost is the lowest ($2.3 billion, CPI-adjusted). Tropical cyclones and flooding represent the second and third most frequent event types (38 and 28), respectively. Tropical cyclones are responsible for the highest number of deaths (3,461), followed by drought/heatwave events (2,993) and severe storms (1,578).

The rising frequency of billion-dollar disaster events

The U.S. has experienced a rising number of events that cause significant amounts of damage. From 1980–2016, the annual average number of billion-dollar events is 5.8 (CPI-adjusted). For the most recent 5 years (2013–2017), the annual average is 11.6 events (CPI-adjusted). 2017 ties 2011 for the highest number of billion-dollar disasters (16 events). The increase in population and material wealth over the last several decades are an important factor for the increased damage potential. These trends are further complicated by the fact that many population centers and infrastructure exist in vulnerable areas like coasts and river floodplains, while building codes are often insufficient in reducing damage from extreme events.

Climate change is also paying an increasing 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 and the potential for extremely heavy rainfall and inland flooding events are most acutely related to the influence of climate change (NCA 2014).

The geography of billion-dollar disaster events by type

The U.S. is weather and climate conscious for good reason, as each geographic region faces a unique combination of persistent hazards. The maps below reflect the frequency with which each state has been part of a billion-dollar disaster event (i.e., the totals do not mean that each state alone suffered $1 billion in losses for each event).

Each disaster type has a distinct footprint of impact over time. We see wildfire impacts largely west of the Plains states, including a few Southeast impacts. The high-frequency inland flooding events often occur in states adjacent to large rivers or the Gulf of Mexico, which is a warm source of moisture to fuel rainstorms. Drought impacts are most focused in the Southern and Plains states where there are billions of dollars in agriculture and livestock assets.

Severe local storm events are common in the Plains and into the Ohio River Valley states. Winter storm impacts are concentrated in the Northeast, not surprising given the propensity for Nor’easters, while tropical cyclone impacts range from Texas to New England, but also include many inland states.

In total, from 1980–2017, the U.S. South/Central and Southeast regions experienced a higher frequency of billion-dollar disaster events than any other region, as shown in the red total disaster map. This map reflects the cumulative diversity, frequency, & severity of weather & climate events impacting these regions.