This incredible map lets you explore Texas before and after Harvey's flooding
To get a head-start on surveying the storm's damage, however, the National Oceanic and Atmospheric Administration has been flying camera-equipped airplanes high above the ground.
So far, the NOAA aerial surveys - the work of the agency's Remote Sensing Division - cover parts of Greater Houston, coastal Texas communities, and other areas devastated by the storm and its record-breaking rainfall.
The pictures not only rival the details in photos taken by satellites hundreds of miles above Earth, but offer an earlier and more extensive look at the destruction. This is because airplanes can fly below thick cloud cover that'd normally block the view from space.
To help people understand the magnitude of Harvey's impact, a mapping-data company called Esri has stitched together NOAA's photos into an interactive tool.
The Esri Disaster Response Program team has highlighted 19 flooded areas in the interactive above.
You can compare before-and-after images for each region by dragging a slider left or right. The tool also shows where streets and highways are below the floodwaters, and even includes a basic search function. (Note: Searching for a location or address sometimes doesn't show "after" Harvey flooding images.)
So far, officials believe more than 40 people have died in the Harvey disaster. The financial toll from the storm may also exceed $190 billion - more than the damage of Hurricane Katrina and Hurricane Sandy combined.