How does a drought last? NASA Satellite are following rainfall and we've seen record rainfall across the mid-west and record droughts across California. But NASA Satellite data from GRACE are also able to track how much water is stored in surface reservoir's and in the ground water below. At this point California is about year behind on rainfall. Meaning that to make up for the lost water that we see as a measure of gravity, you'd have to fill the entire state knee deep with water. (hum)