John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
This mid-week soaking probably won't go one-fifth of the way toward ending it, unfortunately.
After a long stretch of weather as dry as the face of Mars, California is finally getting the drenching it's desperately needed. But will these powerful rainstorms be enough to wash away the state's obstinate drought?
First, take a look at the extent of this sodden system. A massive tentacle of moisture is reaching out of the Pacific and slobbering all over California like a lashing tongue, as shown in this December 2 animation of water vapor:
Wednesday alone, the storm has dumped five inches of rain in parts of Santa Cruz (though most places have gotten much less) and brought thunder and flood advisories to the normally dull-weathered San Francisco Bay. Places where vegetation-killing wildfires have loosened the earth have experienced mudslides, leading to mandatory evacuations. Yet despite this almighty dousing, by the time the skies clear California will still be getting hammered by its fire-spreading, price-inflating, crime-encouraging drought.
Here are the numbers from the National Climatic Data Center, tweeted out Wednesday by meteorologist Eric Holthaus. Say this system unleashes 3 to 4 inches of precipitation onto California. Averaging what could fall and what the state needs, this rain will only go about 18 percent of the way toward moving the state all the way out of drought. More than half of California is thirsting for 18 to 21 inches of precipitation, the other part requires six to nine inches, as shown here:
Even if a biblical deluge were to roll over the horizon tomorrow, splashing the land with 20-plus inches of rain, it still probably wouldn't give the state the moisture it craves. That's because many of its reservoirs today are damp puddles compared to the lakes they were during better, wetter times (a dismal fact that owes much to agricultural pumping). As Holthaus notes, the above graphic "only factors in soil moisture, not replenishment of reservoirs."