It's been a tough summer for drought in the United States and the latest news isn't going to make it it any better. Because it turns out that it's not just the surface that's drying up. There's a drought happening underneath us too.

The map above, which was put together by NASA's Earth Observatory, charts currently available groundwater supplies in comparison to the typical amount of groundwater present at this point in the season over the last 60 years. Red signifies an usually low level of groundwater in comparison to the usual level, while blue means either average or wetter conditions.


Interestingly, there's quite a bit of overlap in the groundwater drought conditions, and the surface drought conditions that we typically monitor when determining a drought's severity, as you can see by comparing the map above with this map of current conditions from the US Drought Monitor:

There are, however, one or two anomalies, mostly in the Pacific Northwest, where despite conditions so dry that wildfires have been a continuous problem, groundwater supplies still show as more plentiful than usual. Unfortunately, the reason for the contrast may simply be due to slower movement of drought underground and not a real symptom of relief.


Map above: Chris Poulsen, National Drought Mitigation Center at the University of Nebraska-Lincoln, based on data from Matt Rodell, NASA Goddard Space Flight Center, and the GRACE science team

Map below: David Miskus, NOAA/NWS/NCEP/CPC