After years of drought, the good news is that California’s snowpack is recovering (and then some). Thanks to a series of unrelenting storms, the snowpack is approaching 200% of its average for the season.
The bad news is that all that snow has to go somewhere. Experts fear warm tropical storms could suddenly melt the ice, resulting in a “killer flood.”
“I hope I’m wrong, but I’m afraid people celebrating the great snows in the Sierra Nevada are seriously underestimating the risk of spring flooding in California, including reservoir operators and state and federal water managers,” scientist Peter Gleick tweeted Saturday.
For the San Joaquin Valley, flooding could come as early as Thursday and Friday.
“Persons living near rivers and streams should closely monitor water levels and be ready to move to higher ground if the threat of flooding becomes imminent,” the National Weather Service warned.
Sacramento is in a particularly perilous situation, writes Dan Walters for CalMatters.
An immense bypass channel protects the city from the Sacramento River – as long as its levees are not breached – but the American River is problematic. Its major control facility, Folsom Dam/Folsom Lake, is generally regarded as too small to handle a major surge of melting snow.
The American’s levees are being strengthened, but the work is not complete. Folsom Dam’s outflow capacity has been expanded by a new spillway. The new works will likely be tested when the massive American River watershed releases its huge snowpack as winter turns to spring and then summer.
Maybe Sacramentans should cross their fingers.
Read more here.