Tucson Rivers: Easy Come, Easy Go

The monsoon returned to southern Arizona with a vengance this weekend. I drove to school for the last day of the intro class I was assistant for on Saturday in a steady downpour and I encountered a couple of minor flooding issues in the streets on the way there. Many, many University buildings had flooded basements (although not, thankfully, the library's below-ground Information Commons computer area). Rain continued on and off on Sunday and Monday as well, leading to some of Tucson's normally bone dry rivers overflowing their banks and flooding local streets and buildings. By way of a visual demonstration, here's a picture of the Rillito River on Monday, July 31st:

Rillito River 07-31-2006

This is a riverbed that is usually completely dry (this is the first time I've ever seen water in the riverbed), and in this picture it is running at nearly full capacity. It actually overtopped its banks a bit further upriver, closing a couple of roads due to flooding on Monday.However, rivers in this part of the world are somewhat ephemeral things. Here's a pic of the same river taken barely more than 24 hours later:

Rillito River 08-01-2006

Quite a difference, ain't it? (Yes, that's the same view, and yes, that's the same bridge in both pics).

Unless there's another deluge this weekend, I expect the river will be dry again by Monday....