Researchers at the National Science Foundation National Centre for Atmospheric Research (NSF NCAR) in the United States examined data from 2017 Twitter (now X) about Harvey and Irma. The researchers discovered that people’s responses to later warning messages are influenced by forecast information sent during the early phases of storm development when the threat posed by a hurricane is unknown.
The study team also determined how reliable organisations, including the National Weather Service, television meteorologists, and emergency management, can interact with members of the community who are at danger more effectively.
When we began this research, a lot of work had been done analyzing Twitter data in the post-disaster space, and we were interested in how people were responding to weather forecast information in earlier stages, especially as predictions change,
Twitter provided a natural laboratory for us to look at what communications people are responding to and what information they are sharing. This kind of research can help the meteorological community learn what are the most important things to communicate and how to improve that messaging.
Rebecca Morss
2017 saw the occurrence of both Harvey and Irma, however their respective behaviours were extremely different. Harvey was an unusual storm that strengthened quickly before hanging out over the Texas coast for a few days, causing catastrophic flooding in Houston. Irma, on the other hand, was predicted well in advance of landfall and moved over land in a more normal manner, posing a serious risk from powerful winds and storm surges. When taken as a whole, the two storms offered complimentary information regarding the many hurricane hazards that should be discussed in the face of diverse degrees of uncertainty.
The NSF NCAR researchers were able to access a comprehensive log of real-time information sharing and response patterns on Twitter. The study team concentrated on tweets published by reliable sources and created a collection of tweets pertinent to each cyclone.
The researchers categorised tweets according to the visuals used and searched for trends in the picture kinds that were most often retweeted and engaged with to assess how the tweets informed those at danger of the storms. To learn more about how residents in at-risk locations comprehend and react to a hurricane’s changing danger, the researchers also looked at the content of Twitter responses in response to forecasts and warnings.
In early stages of the threat, we could see a really clear cadence that every six hours there would be an uptick in Twitter conversation about the hurricanes,
This was driven by the National Hurricane Center putting out updated forecast information. That information would then be redistributed by broadcast meteorologists, emergency managers, news media, and weather enthusiasts, and the conversation would grow from there. It really highlighted the key role of the National Weather Service in leading this communication.
Robert Prestley
Moreover, Morss and Prestley noted that during a storm, the functions of local and national National Weather Service (NWS) offices changed. Local NWS offices took the lead in producing locally relevant forecast and warning content as the storms started to affect towns, while NWS centres like the National Hurricane Centre played a key role in disseminating information as the storm grew.
The study discovered a number of picture kinds that were often employed to provide information on the possibility of a storm. The “cone of uncertainty” image received the most retweets out of all of them.
The cone of uncertainty displays a tropical storm’s current position along with its likely centre course, with a cone-shaped area surrounding it to indicate the track’s uncertainty due to past inaccuracies. Cone photos have limits, as other studies have demonstrated. One such restriction is the absence of information regarding the hazards to those beyond the cone, which may mislead people to believe that regions outside the cone are safe.
There’s a clear need for better uncertainty visualizations, especially in the forecast and warning period when people are looking for information, but there’s not yet enough certainty to say specifically where or what the impacts will be,
The cone is not necessarily equipped to do that. The question is how to maintain the visibility of an image people are accustomed to while more effectively communicating hurricane risks to different populations.
Robert Prestley
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The researchers also determined how the two hurricanes’ picture contents differed from one another. For example, tweets with photos of floods and a lot of rain were heavily shared during Hurricane Harvey. The high level of interaction with such tweets highlights the need of credible sources to adjust their messaging to highlight the various threats that each storm poses.
Watch and warning imagery was the least interactive picture kind. The NWS has issued watches and advisories for several dangers such as tornadoes, strong winds, and flash floods, and this information is included in these graphics. These graphics, which frequently have text and visualisations with the same or comparable formatting, are produced by automated programmes.
The fact that most of these watches and warnings are only valid for brief periods of time and cover small geographic areas may help to explain why so few people have retweeted them. More study is advised by Morss and Prestley on how to better communicate watch and warning information on social media, including when and how to employ automated tweets to quickly spread more readable content.
A new understanding of how individuals react to changing information regarding natural catastrophe threats was developed by Morss, Prestley, and colleagues using Twitter, despite the fact that numerous aspects of the site have altered since the NSF NCAR research team completed their study. In order to better understand how individuals respond to impending natural catastrophes, the researchers are now utilising other research techniques, such as surveys conducted prior to, during, and following weather occurrences. The questions utilised in this continuing study were influenced by the Twitter studies.
The knowledge gained can help professional weather communicators improve how they use social media networks as a vibrant resource for improving disaster communication.
Source: NCAR News
Journal Reference: Morss, Rebecca E., et al. “Information dissemination, diffusion, and response during Hurricane Harvey: Analysis of evolving forecast and warning imagery posted online.” Natural Hazards Review 25.3 (2024): 04024020. DOI 10.1061/NHREFO.NHENG-1802
