It seems a tautology that rain reduces drought. Yet our water picture is so surreal that the National Weather Service just said, “. . . local rainfall in Southern California does not necessarily help the drought situation.”
How so? It hinges on the meaning of “the drought situation.” We are involved in two drought situations.
One is related to the below normal rainfall we’ve received on our very roofs in Southern California over the last few years.
The other is about the below normal rainfall most of the Western U.S. has received over the last few years, especially Northern California and the Colorado River watershed.
You’d think the amount of rain falling on our roofs — the local drought situation — would be the more important of the two, but then you’d be forgetting where the water from our faucets originates. The water we use comes mostly from Northern California and the Colorado River. The rain that falls on our roofs goes basically unused and is treated like sewage, and that’s why the NWS can rightly say that the deluge we received in mid-July had little to no impact on our drought situation.
But here’s a scenario that is more bizarre than the above: As the meteorologist at the California Weather Blog puts it, “Well-developed El Niño conditions already exist in the tropical Pacific Ocean.” El Niño is here. The impacts? El Niño conditions have a strong correlation with above normal precipitation in Southern California. In other words, a wet winter is likely on the way. However, El Niño conditions do not have as strong a correlation with above normal precipitation in Northern California. Some El Niño years are relatively dry for Northern California.
So, come February, we could be simultaneously dealing with flood damage in our living rooms while seeing signs in road medians advising us “When in Drought . . . ”