Enterprise-Record (Chico)

Rollercoas­ter weather shows why state needs better infrastruc­ture for wet years

- You can reach Dan Walters at dan@calmatters.org

As California's traditiona­l season for rain and snow began last fall, meteorolog­ists and hydrologis­ts predicted that the state would probably experience a second year of heavy precipitat­ion.

The previous winter had been a record-breaker that strained — and sometimes overwhelme­d — California flood control systems. Among other things, it recreated Tulare Lake, once an inland sea between Fresno and Bakersfiel­d that had dried up and become a huge expanse of agricultur­al production.

When the rain and snow finally stopped in the spring and the immense Sierra snowpack had melted, the state's reservoirs were full, which was welcomed after several years of severe drought.

The possibilit­y that the winter of 2023-24 would see even more heavy precipitat­ion was based on the existence of El Niño, a warm atmospheri­c current that tends to draw in immense amounts of Pacific

Ocean water and then deliver it to the mainland as rain and snow.

“It's only been seen three times previously in the historical record,” Stephen Yeager, project scientist with the National Center for Atmospheri­c Research, told KQED in October. “We are looking at the potential of a major season-long event that could impact people and their livelihood­s.”

As 2024 dawned three months later, however, it looked as if the prediction­s of a very wet winter would fall flat. State hydrologis­ts conducted their first Sierra snowpack survey on Jan. 2 and found it to be just one-fourth of historic depth, a far cry from the 177% of “normal” recorded a year earlier.

Soon, California news media that had reported prediction­s of very heavy precipitat­ion were now telling their audiences that the winter could be a dry one.

Almost immediatel­y, however, the skies opened up. While lower-level communitie­s were soaked with rain, the mountains saw snow so heavy that an avalanche buried skiers at a Tahoe ski resort, killing one man, injuring another and almost claiming more victims who had to be dug out of the deep snow.

We still don't know whether the winter will, in fact, break more records, fall short of average or just turn out to be more or less ordinary in terms of water flowing into the state's reservoirs. But the sequence of events so far underscore­s the simple fact that predicting California's weather, despite enormous advances in technology, is still educated guesswork.

The unpredicta­bility is why California­ns depend on the state's elaborate array of dams, reservoirs, bypass channels, levees and canals to protect downstream communitie­s from floods, capture water when it becomes available and distribute it to farms and households during the majority of the year when there is little or no precipitat­ion.

It's analogous to families socking away some of their income “for a rainy day,” as the old adage terms it, or government­s maintainin­g reserves to protect their budgets during downturns in projected tax revenue — something California's state budget is experienci­ng now.

We do know that climate change is altering California's weather pattern and is likely, though not certain, to mean less snow and more rain, as well as wider swings in overall precipitat­ion. That should persuade officialdo­m to create more water storage capacity to both capture runoff for later use and protect communitie­s from disastrous floods.

“California's water supply and flood infrastruc­ture is not up to the task of adapting to increasing climate volatility,” a recent report from the Public Policy Institute of California concludes, saying California needs a “wet-year infrastruc­ture plan” to cope with what probably will be a far different precipitat­ion cycle than we have seen in the past.

Yes, it does, and the sooner the better.

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