Revisiting Hurricane Dorian
How NASA and partners respond to disaster events with data
What happened?
On the blustery afternoon of August 24th, about 800 miles (1,300 kilometers) off the Caribbean island of Barbados, the fifth weather system of the season appeared. Within a matter of hours, the National Hurricane Center (NHC) in the United States watched the tropical depression grow into a tropical storm, and they gave it the name Dorian.
Infrared clouds August 29 to September 8 by NOAA .
Over the next several weeks, Dorian grew to a powerful category 5 hurricane.
After barely missing Puerto Rico, it tore through the Bahamas, narrowly avoided a hard landing on the East Coast of the United States, and went on to knock out power for 400,000 homes in Nova Scotia, Canada.
For many, the storm had severe consequences; especially for those living in the Bahamas.
Two Bahamian islands—Great Abaco and Grand Bahama—were hit hardest by the storm.
Tracking Dorian
Dorian's wind swath
The National Hurricane Center collected (and made publicly available) data about the hurricane's wind swath, providing a visual indication of the storm's force as it moved north.
Hurricane Dorian best track and wind swath data by NHC .
The two outermost regions of the wind swath comprise tropical-storm force winds, ranging from 34 to 63 knots, or 39 to 73 mph (63-117 kph).
The innermost region of the wind swath is where the hurricane-force winds are found. These winds exceed 63 knots, consisting of hurricane categories 1 through 5 on the Saffir-Simpson scale.
The storm approaches the Bahamas and Florida
As the threat from Dorian became imminent, disaster programs across the Caribbean kicked into high gear.
NASA coordinated with several federal units (including NHC, NOAA, and FEMA) and Caribbean nations to prepare data from satellites in Earth's orbit.
Flooding and damage estimates, imagery of lights at night, and cumulative rainfall were all made available to help crisis managers send resources where they were most needed.
Winds batter the islands of Great Abaco and Grand Bahama
On the evening of September 1st, the world watched as Hurricane Dorian—now a category 5 hurricane with winds clocked at 160 knots (184 mph / 296 kph)—landed on the Bahamian island of Great Abaco.
Dorian traced along the island chain from east to west. It stalled over Grand Bahama, pummeling its inhabitants for more than 40 hours.
A member of the Coast Guard with a rescued survivor of Hurricane Dorian. Photo by Coast Guard News .
Seeing beneath Dorian
The hurricane's swirling rain bands seemed to obscure everything. But sensors looking on from Earth's orbit revealed what took place underneath.
A satellite observes Hurricane Dorian over the Bahamas. Video by NASA .
Flooding
Using radar feeds from an Earth-observing satellite system known as Copernicus Sentinel-1, NASA and partners were able to estimate which areas had flooded.
Even before the storm had abated, disaster responders used this information to understand which areas were most likely under water.
An aerial view of Dorian's destruction in the Bahamas. Photo by Coast Guard News .
Copernicus Sentinel-1 ARIA flood and damage proxy data by the Advanced Rapid Imagining and Analysis team at the Jet Propulsion Laboratory and California Institute of Technology in Pasadena California, in collaboration with the Earth Observatory of Singapore. Contains modified Copernicus Sentinel data (2019). Data provided by NASA.
Damage
Meanwhile, NASA used the same Sentinel-1 radar to calculate an estimate of the areas worst hit by the hurricane.
With homes leveled and swathes of woodland stripped of limbs and foliage, estimates showed vast areas of damage across the two islands.
A Coast Guard helicopter and crew performs a search and rescue mission in Dorian's wake. Photo by Coast Guard News .
Lights at night on August 29th
Meanwhile, another satellite—the Suomi-NPP—looked on and captured images of nighttime lights to help identify areas where power was lost.
Two days before Dorian arrived, the cities of Freeport, Grand Bahama and Marsh Harbour, Great Abaco were lit brightly.
Suomi-NPP VIIRS DNB data for August 29 and September 9 provided by NASA .
Lights out on September 9th
Days later, lights in Freeport were scattered, while power in Marsh Harbour had gone dark.
Despite widespread power outages and damaged infrastructure, rescue efforts continued unabated.
Members of the Coast Guard help evacuate those stranded in areas hardest hit by Dorian. Photo by Coast Guard News .
On the ground
Imagery missions flown by NOAA in the immediate aftermath of Hurricane Dorian created an even more exact picture to complement and verify data feeds streaming from orbital sensors.
The real power of data amidst disaster events is in the sharing of information across agencies.
Capable of discerning objects as small as 25 centimeters, the following high resolution imagery reveals the path of destruction laid across the community of Marsh Harbour on the Bahamian island of Great Abaco.
Before and after...
A birds-eye-view that makes clear Dorian's impact. Pre-event 15 meter imagery provided by Earthstar Geographics and Esri . Post-event 25 centimeter imagery by NOAA .
Extent of the damage, annotated...
A better picture
Orbital sensors—and the high resolution, real-time data that they provide—have revolutionized the way we see disasters as they happen.
But it's more than just about seeing. NASA, working with their counterparts at NOAA, FEMA, and elsewhere are sharing ever more precise data. With better information, emergency responders have the tools to make informed decisions at critical moments. Deploying this data helps save lives.
About NASA Disasters Program
The Disasters Applications area promotes the use of Earth observations to improve prediction of, preparation for, response to, and recovery from natural and technological disasters. Learn more here .
About ArcGIS StoryMaps
Esri's StoryMaps team supports authors to elevate their storytelling and communicate their mission to the world. Get started with ArcGIS StoryMaps here .
Credits
Data and imagery is courtesy of the tireless work of countless teams from across the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA), and their partners. Esri's StoryMaps team created the data visualizations and produced this story.
- Jeremy Kirkendall | Disasters GIS Lead, NASA
- Ross Donihue | Product Engineer, Esri
- Greyson Harris | Product Engineer, Esri
