Hurricane Irma crossed the Florida Keys the morning of September 10, 2017, as a Category 4 hurricane with winds of 130 miles per hour. Besides damage done to structures on the islands, the storm also stirred the waters.

A natural color Landsat image acquired four days after the storm contrasts with an image acquired in March. The murky green-blue color is near-surface sediment churned up by strong winds. Landsat’s green band penetrates the shallow water to reveal the extent of sediment.

The distinct line south of the Keys where the sediment ends is a steep drop-off, the edge of the continental shelf on which the Keys sit. The dark color indicates deeper water compared to the shallower water of the shelf.

In the close-up image from March, a wave pattern emerges near Marquesas Keys. These aren’t water waves but sand ripples seen just under the clear water. After the storm, those ripples are obscured by suspended sediment in the turbid water.

Minor hurricanes may enhance biodiversity by clearing the reef of dead organisms. Major hurricanes like Irma, however, can damage the marine habitat. The Florida Keys National Marine Sanctuary is still assessing any damage that might have been done to marine habitats, and future Landsat acquisitions will be useful in monitoring the changes that occurred.