The U.S. and British Virgin Islands
Natural color satellite imagery from NASA reveals the green and lush tropical islands of St. Thomas, St. John, Virgin Gorda and Tortola turned over to completely brown after Irma raked across them.
“There are a number of possible reasons for this,” NASA said. “Lush green tropical vegetation can be ripped away by a storm’s strong winds, leaving the satellite with a view of more bare ground. Also, salt spray whipped up by the hurricane can coat and desiccate leaves while they are still on the trees.”
The Keys and South Florida
As the storm ripped through the Keys and into South Florida, it moved around an enormous amount of sediment, as shown in the image below.
“The light blue color shows sediment suspended in the water, kicked up by the intensity of the storm,” said NOAA. This imagery was acquired from the NOAA-NASA Suomi NPP satellite, created by combining data from several color channels of one its instruments sensitive to different wavelengths of light.
Here is a close-up of the Florida Keys, showing the sediment displacement:
And here is a close-up that includes South Florida:
Aerial imagery, obtained by NOAA’s National Geodetic Survey, also reveals dramatic before and after scenes of damage to land and structures.
Below are two views from the Keys, which show vegetation stripped away and buildings ruined:
And here is a before-and-after view from Marco Island, where the storm made its second U.S. landfall, which shows several separate golf ponds joined together into what ostensibly becomes a large lake:
Irma, which maintained 180-mph-plus winds for a world-record-setting 37 hours, drew a tremendous amount of heat from the ocean — which was warmer than normal when the storm passed over. In its wake, it left behind a trail of cooler-than-normal water.
This is a normal process when hurricanes pass over a section of the ocean, exhausting the supply of warm water near the surface and drawing up cooler water deeper down in a process known as upwelling.
In addition to the formation of Irma’s wake, the cool pool of water left behind by Hurricane Harvey is seen both before and after Irma in the northwestern Gulf of Mexico, while Hurricane Katia’s wake is seen in the second frame (after it had made landfall on Sept. 7).
More stories on the aftermath of Irma