Houston's elevation in relation to sea level is pretty low and now it's even lower thanks to the weight of the water from Hurricane Harvey.

With parts of Houston receiving more than fifty inches of rainwater, flood waters caused by Hurricane Harvey were pretty slow to drain. As that water sat there, it compacted the ground even more. Chris Milliner, who works as a NASA scientist at the Jet Propulsion Laboratory, tweeted out a graphic of just how the sheer weight of the flood waters changed the Houston landscape.

The graphic shows GPS data from the Nevada Geodetic Laboratory showing the vertical shift in the land and bedrock due to the heavy rainfall. The rainfall from Harvey, guestimated at 20 trillion gallons, weighed approximately 170 trillion pounds on the region. Because of all this extra weight compacting the land around Houston, the region actually sank two centimeters in some areas.

That's not a lot, two centimeters, but when you think about it and all that weight, that's a pretty big deal.