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Harvey News and Research

We'll be periodically updating this page with new information regarding Hurricane Harvey and and research into it. If you're interested in participating in some research by submitting casual rainfall observations during Harvey, you can take the casually observer survey linked in the left sidebar.


National Hurricane Center Tropical Cyclone Report

"Hurricane Harvey"

Summary: Harvey started as a typical weak August tropical storm that affected the Lesser Antilles and dissipated over the central Caribbean Sea. However, after re-forming over the Bay of Campeche, Harvey rapidly intensified into a category 4 hurricane (on the SaffirSimpson Hurricane Wind Scale) before making landfall along the middle Texas coast. The storm then stalled, with its center over or near the Texas coast for four days, dropping historic amounts of rainfall of more than 60 inches over southeastern Texas. These rains caused catastrophic flooding, and Harvey is the second-most costly hurricane in U.S. history, after accounting for inflation, behind only Katrina (2005). At least 68 people died from the direct effects of the storm in Texas, the largest number of direct deaths from a tropical cyclone in that state since 1919.



 "Assessing the present and future probability of Hurricane Harvey's rainfall"

Abstract: We estimate, for current and future climates, the annual probability of areally averaged hurricane rain of Hurricane Harvey’s magnitude by downscaling large numbers of tropical cyclones from three climate reanalyses and six climate models. For the state of Texas, we estimate that the annual probability of 500 mm of area-integrated rainfall was about 1% in the period 1981–2000 and will increase to 18% over the period 2081–2100 under Intergovernmental Panel on Climate Change (IPCC) AR5 representative concentration pathway 8.5. If the frequency of such event is increasingly linearly between these two periods, then in 2017 the annual probability would be 6%, a sixfold increase since the late 20th century.

Emanuel, K. (2017). Assessing the present and future probability of Hurricane Harvey’s rainfall. Proceedings of the National Academy of Sciences, 201716222. [Date retrieved 2/13/2018]

"Attributable Human‐Induced Changes in the Likelihood and Magnitude of the Observed Extreme Precipitation during Hurricane Harvey"

Abstract: Record rainfall amounts were recorded during Hurricane Harvey in the Houston, Texas, area, leading to widespread flooding. We analyze observed precipitation from the Global Historical Climatology Network with a covariate-based extreme value statistical analysis, accounting for both the external influence of global warming and the internal influence of El Niño–Southern Oscillation. We find that human-induced climate change likely increased the chances of the observed precipitation accumulations during Hurricane Harvey in the most affected areas of Houston by a factor of at least 3.5. Further, precipitation accumulations in these areas were likely increased by at least 18.8% (best estimate of 37.7%), which is larger than the 6–7% associated with an attributable warming of 1°C in the Gulf of Mexico and Clausius-Clapeyron scaling. In a Granger causality sense, these statements provide lower bounds on the impact of climate change and motivate further attribution studies using dynamical climate models.

Risser, M. D., & Wehner, M. F. (2017). Attributable Human‐Induced Changes in the Likelihood and Magnitude of the Observed Extreme Precipitation during Hurricane Harvey. Geophysical Research Letters44(24). [Date retrieved 2/13/2018]

"Attribution of extreme rainfall from Hurricane Harvey, August 2017"

Abstract: During August 25–30, 2017, Hurricane Harvey stalled over Texas and caused extreme precipitation, particularly over Houston and the surrounding area on August 26–28. This resulted in extensive flooding with over 80 fatalities and large economic costs. It was an extremely rare event: the return period of the highest observed three-day precipitation amount, 1043.4 mm 3dy−1 at Baytown, is more than 9000 years (97.5% one-sided confidence interval) and return periods exceeded 1000 yr (750 mm 3dy−1) over a large area in the current climate. Observations since 1880 over the region show a clear positive trend in the intensity of extreme precipitation of between 12% and 22%, roughly two times the increase of the moisture holding capacity of the atmosphere expected for 1 °C warming according to the Clausius–Clapeyron (CC) relation. This would indicate that the moisture flux was increased by both the moisture content and stronger winds or updrafts driven by the heat of condensation of the moisture. We also analysed extreme rainfall in the Houston area in three ensembles of 25 km resolution models. The first also shows 2 × CC scaling, the second 1 × CC scaling and the third did not have a realistic representation of extreme rainfall on the Gulf Coast. Extrapolating these results to the 2017 event, we conclude that global warming made the precipitation about 15% (8%–19%) more intense, or equivalently made such an event three (1.5–5) times more likely. This analysis makes clear that extreme rainfall events along the Gulf Coast are on the rise. And while fortifying Houston to fully withstand the impact of an event as extreme as Hurricane Harvey may not be economically feasible, it is critical that information regarding the increasing risk of extreme rainfall events in general should be part of the discussion about future improvements to Houston's flood protection system.

van Oldenborgh, G. J., van der Wiel, K., Sebastian, A., Singh, R., Arrighi, J., Otto, F., ... & Cullen, H. (2017). Attribution of extreme rainfall from Hurricane Harvey, August 2017. Environmental Research Letters12(12), 124009. [Date retrieved 2/13/2018]

"Hurricane Harvey provides lab for U.S. forecast experiments"

Summary: For years, U.S. forecasters have envied their colleagues at the European Centre for Medium-Range Weather Forecasts in Reading, U.K., whose hurricane prediction models remain the gold standard. But two innovations tested during Hurricane Harvey, one from NASA and another from the National Oceanic and Atmospheric Administration, could help level the playing field. The storm provided the first high-profile test for the next-generation weather model developed for the National Weather Service, which can zoom in on storms. And Harvey will help calibrate the Cyclone Global Navigation Satellite System, a NASA array of eight microsatellites that aim to detect the maximum wind speed of storms through their veil of moisture.

Voosen, P. (2017). Hurricane Harvey provides lab for U.S. forecast experiements. Science. 357(6354). 


 Past Conference Presentations

"When the Impossible Becomes Possible" Keynote Presentation (SSPEED Conference 2018)

Nielsen-Gammon, J. (2018). When the Impossible Becomes Possible. Severe Strom Prediction, Education, and Evacuation from Disasters Conference. Rice University, Houston, TX. [Presented 21 February 2018]

"Examining Societal Impacts of the 2017 Atlantic Hurricane Season: Informatics and Engineering" (AGU Fall Meeting 2017)

Abstract: In 2017, the Americas have dealt with numerous hurricane events of historic proportion. Two storms have made landfall in the US in recent weeks after causing devastation to numerous Caribbean nations. Hurricane Harvey arrived as a Category 4 near Rockport, TX on August 26, 2017 followed by Hurricane Irma on September 10, 2017 arriving at Cudjoe Key, FL. Hurricane Maria crippled islands in the Caribbean before arriving in Puerto Rico on September 19, 2017. This session will be organized as multiple sessions and seeks a wide breadth of contributions focusing on the events of these storms, including crowdsourced data and social media in disaster response; policy implications; high resolution remote sensing; flooding and infrastructure damage; impacts on the environment and human health; changing coastal landscapes; oceanographic, atmospheric, and climatic factors contributing to the storm; data access and assimilation; HPC and cloud computing for real time analysis.

Cervone, G., Nittrouer, J.A., Thompson, C.M,., Wyborn, L.A. (2017). Examining Societal Impacts of the 2017 Atlantic Hurricane Season: Informatics and Engineering. American Geophysical Union Fall Meeting 2017. New Orleans, LA. [Presented 13 December 2017]

"Hurricane Harvey's Impacts across South Texas" (AMS Annual Meeting 2018)

Abstract: Category 4 Hurricane Harvey made landfall along the Middle Texas Coast during the evening hours on August 25th, 2017. Harvey was the first major hurricane to strike the Middle Texas Coast since Hurricane Celia back on August 3rd, 1970. Harvey produced widespread damage, both from winds and storm surge, to many communities across South Texas, some of which will take years to fully recover. An overview of Harvey and its impacts to South Texas will be discussed in this presentation.

Buchanan, M.E. (2018). Hurricane Harvey's Impacts across South Texas. American Meteorological Society Annual Meeting 2018. Austin, TX. [Presented 9 January 2018]

"NASA Earth Science Disasters Program Response Activities During Hurricanes Harvey, Irma, and Maria in 2017" (AMS Annual Meeting 2018)

Abstract: The 2017 Atlantic hurricane season included a series of major hurricanes that impacted the Gulf Coast of the United States, and the Caribbean breaking a 12-year drought of major hurricane landfalls in the mainland United States (Harvey and Irma), with additional extensive impacts from the combination of Irma and Maria felt in the Caribbean. These storms caused widespread devastation across Caribbean islands, U.S. territories, and impacted states resulting in a significant need to support federal partners in response to these destructive weather events.

The NASA Earth Science Disasters Program provided support to federal partners including the Federal Emergency Management Agency (FEMA) and the National Guard Bureau (NGB) by leveraging remote sensing and other scientific expertise through the NASA Centers, principal investigator-led research activities, and partners in academia throughout the country. The NASA Earth Science Disaster Program leveraged NASA mission products from the Global Precipitation Measurement (GPM) mission to monitor cyclone intensity, assist with cyclone center tracking, and quantifying precipitation. Multispectral imagery from the NASA-NOAA Suomi-National Polar-Orbiting Partnership (NPP) mission and the Visible Infrared Imaging Radiometer Suite (VIIRS) Day-Night Band proved useful for monitoring power outages and recovery. Synthetic Aperture Radar (SAR) data from the Copernicus Sentinel-1 satellites operated by the European Space Agency were used to create flood inundation maps as well as damage assessment maps that were useful for FEMA’s flood and damage density mapping.

Using additional datasets made available through the USGS Hazards Data Distribution System (HDDS) and the activation of the International Charter: Space and Major Disasters, the NASA Earth Science Disasters Program was able to create additional derived flood products from both optical and radar remote sensing platforms, including products, along with PI-led efforts to derive products from other international partner assets such as the Italian Space Agency’s Constellation of Small Satellites for the Mediterranean Basin Observation (COSMO)-SkyMed system.

Given the significant flooding impacts from Harvey in the Houston area, NASA provided airborne L-band collections from the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) system which provided daily monitoring capable of capturing the evolution of record flooding, helping to guide response and mitigation decisions for critical infrastructure and public safety. We will provide an overview of the response activities and data products provided by the NASA Earth Science Disasters program, partnerships with federal end-users and the International Charter, and preliminary feedback from end-user partners during response efforts following Hurricanes Harvey, Irma, and Maria.

Bell, J.R., et. al. (2018).  NASA Earth Science Disasters Program Response Activities During Hurricanes Harvey, Irma, and Maria in 2017. American Meteorological Society Annual Meeting 2018Austin, TX. [Presented 9 January 2018]

"Harvey: An Exceptional Rainfall Event(AMS Annual Meeting 2018)

Abstract: The rainfall associated with Harvey was truly exceptional. It broke numerous United States records for point total precipitation as well as precipitation over a wide range of areas and durations. Indeed, Harvey may have exceeded storm total probable maximum precipitation values. This talk will compare Harvey to other exceptional rainfall events and describe efforts under way to collect and analyze as much rainfall data from Harvey as possible and to provide a comprehensive set of rainfall analyses for further study.

Nielsen-Gammon, J.W.(2018). Harvey: An Exceptional Rainfall Event. American Meteorological Society Annual Meeting 2018Austin, TX. [Presented 9 January 2018]

"Hurricanes Harvey, Irma, and Maria: Did Climate Change Play a Role?" (AMS Annual Meeting 2018)

Abstract: What do climate models and analysis of long-term climate data indicate about a possible role for climate change in the recent powerful Atlantic hurricanes of 2017? Hurricane Harvey's record rainfall totals were primarily due to the storms slow movement over southeast Texas. There is no compelling evidence that climate change is making the occurrence of slowly moving landfalling hurricanes in the region, such as Harvey, more or less likely. Hurricane Irma was an exceptionally intense storm. It likely set a global record for the satellite era as the longest duration that a tropical cyclone has maintained surface wind speeds of at least 185 mph. There is indirect evidence that the severity of some of the impacts of the population of hurricanes in general, specifically storm surge levels and rainfall rates, are being increased by anthropogenic climate change through increased sea level and atmospheric moisture. However, despite strong physical arguments, a caveat is that increased hurricane surge levels and hurricane rainfall rates have not been clearly detected in observed climate data. Similarly, we expect that Atlantic (and global) hurricanes will become more intense on average as the climate continues to warm, but again there is no clear observational evidence to date that such a signal has emerged from the background of natural variability. Climate change is further expected to increase the global frequency of very intense (Category 4-5) storms similar to these hurricanes in the future, but quantifying the effect remains difficult, and there is only low confidence for such an increase in the Atlantic basin. Increased occurrence of very intense hurricanes in models is a mixture of increasing average intensity, partially offset by decreasing overall frequency of hurricanes, leading to less overall confidence in the change.

Knutson, T.R.(2018). Harvey: An Exceptional Rainfall Event. American Meteorological Society Annual Meeting 2018. Austin, TX. [Presented 9 January 2018] 

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