Storm Provides Some Drought Relief, But Water Shortage Prevails

The last few days of rain and snow provided some welcome relief, but don’t be fooled — the water shortage is far from over. That wet trend will have to continue if there’s to be any real dent in the ongoing drought.

Burbank, LAX, Lancaster and other places in Los Angeles County broke some rainfall records, but when it comes to drought and much of the Southland’s drinking water supply, it’s the snowfall up north that really matters.

“These November storms are starting up right when we would usually expect them,” said Sean de Guzmán, snow and water supply forecast manager for the California Department of Water Resources. “But now it's still really early in the year to see what may actually happen.”

So far, so good, but what happens in the next few months is the big question.

“In the Sierra Nevadas, especially in the northern Sierra, the majority of our rain and snow falls during December, January and February,” said De Guzmán. “That usually accounts for about half of the snow and rain that we get in a season.”

The Sierra mountains saw as much as four feet of snow over the last few days, according to the Central Sierra Snow Lab, a U.C. Berkeley research field station. When that snow melts, it’s siphoned into the reservoirs that supply most of L.A.’s water.

Last year there was an even bigger blockbuster start to the wet year, with the snowiest December on record. But that quickly went bust. Instead of ongoing storms from January through March — the heart of California’s wet season — those three months ended up being the driest in more than 100 years.

“We foresee a high likelihood that climate change will create winters that have both very wet and very dry months in the same winter,” said Daniel Swain, a climate scientist at UCLA.

He said the whiplash effect of bigger but fewer storms and longer and drier hot periods are a telltale sign of how global heating is changing California’s climate norms. That may not seem like such a big deal so long as overall we end up with similar amounts of snow and rain as normal years, but unfortunately it’s not so simple.

As Earth’s temperature increases with climate change, so does the rate of evaporation, causing soil to dry out faster. That makes it harder for water to seep in, help plant growth and refill underground aquifers. Furthermore, increased evaporation actually leads to bigger snow and rainstorms — and when those big storms hit, especially with that dried out soil, that can lead to bigger and more dangerous floods.

We can’t fully predict what this winter will bring, Swain said, but so far it still looks like a drier-than-average year ahead.