It is June in Santa Elena, Costa Rica, and we are in our hotel room at Valle Escondido (‘Hidden Valley’). The rain pours in sheets off of the tin metal roof, and I find myself wondering: just how much water can the sky hold? Funny enough, I know the answer to that. In numerical climate models, we can calculate something called precipitable water. This is a measure of how much water we would have pooling at our feet if the sky opened up and dropped everything at once. In the Tropics it’s somewhere around 6-10 centimeters. In the firehose of water pounding the pavement outside the window, I believe that’s an accurate estimate.
