Fig 1.
Hurricane Matthew and the study area for the regional analysis (left) and the local analysis (right).
The Hurricane Matthew track was obtained from the National Oceanic and Atmospheric Administration (NOAA: http://www.nhc.noaa.gov/gis/archive_besttrack.php).
Fig 2.
Overview of the research approach.
Table 1.
Twitter datasets.
Fig 3.
Temporal distribution of Matthew-related tweets for the five states.
a) All states b) Florida, 59.7% of the tweets c) Georgia, 10.2% of the tweets d) South Carolina, 12.4% of the tweets e) North Carolina, 12.9% of the tweets f) Virginia, 4.9% of the tweets. Shaded area represents daily tweets, while the hourly tweets are shown on the line graph. Numbered dots indicate the selected key events during the time period: 1. South Carolina evacuation order. 2. Georgia evacuation order. 3. Hurricane eye offshore Daytona Beach (FL). 4. Hurricane eye offshore Savannah (GA). 5. Hurricane eye offshore Charleston (SC). 6. Hurricane eye offshore Wilmington (NC).
Fig 4.
Temporal distribution of evacuation-related tweets.
Numbered dots indicate the key events during the time period: 1. South Carolina evacuation order (SC residents in the coastline counties were mandated to evacuate on October 4th); 2. Georgia evacuation order (GA residents on the east of Interstate 95 were mandated to evacuate on October 6th); 3. Florida evacuation warning by Florida Governor (1.5 million of residents living in evacuation zones on the Atlantic coast of Florida were urged to evacuated on October 6th); 4. Landfall near McClellanville, South Carolina (October 8th, 1500UTM).
Fig 5.
Spatial distribution of Matthew-related Twitter activity in counties with more than 50 active users.
Fig 6.
Correlation between Twitter activity per county and distance to Hurricane Matthew.
Fig 7.
Workflow to obtain the local users.
Fig 8.
Response to the evacuation order of the 1384 local Twitter users.
(a) Local-user locations during pre-evacuation period (10/02-10/04). (b) Local-user locations during post-evacuation period (10/07 6pm– 10/09 10am). Blue dots represent the users who moved outside of the risk area (eight coastal counties), and red dots were the users who did not evacuate.
Table 2.
Evacuation rates and estimated evacuees by conglomerate.
Fig 9.
Evacuation destinations from South Carolina during Hurricane Matthew.
Table 3.
Evacuation destinations from South Carolina during Hurricane Matthew.
Table 4.
Return after evacuation.