More Sacramento rain and Sierra snow keep eyes on rising reservoirs and streams
A sunny and dry Monday across the Sacramento region gave way to yet another storm system overnight that is expected to further swell local rivers and reservoirs, soak a saturated valley floor and add to already-historic Sierra snowpack.
“The main story is a weak, atmospheric river storm that will bring significant mountain snow, and widespread, lower elevation rain,” National Weather Service forecaster Courtney Carpenter said in her Monday morning briefing.
“It’s not a huge amount, or a super wet system,” Carpenter said. “But given the fact that we’re saturated, we’ll continue to see those issues with urban and small stream flooding, especially during any thunderstorms that pop up — and the potential for additional mud and rock slides in the foothills — because we are just very saturated at this point,” she said.
Anywhere from a quarter-inch to a half-inch of rain will fall in the northern San Joaquin Valley; 1 to 2 inches in the Sacramento region and as much as 3 inches in the Sierra foothills.
Rain and gusty winds on the valley floor will mark this latest push, but the storm will still be strong enough to dump another heavy load of snow in the high country — as much as 1 to 3 inches an hour as the main band of weather pushes east.
Carpenter said she expects a foot or more of new snow across the higher elevations above 4,000 feet, and with it, Carpenter said, more accumulation resting on snow-weary homes and buildings across the mountain communities.
Rivers, reservoirs monitored
It’s not as much precipitation as in the previous systems that have drenched the region, but Carpenter said it’s still enough to raise concerns and keep river and reservoir monitors on watch.
Folsom Dam is at 66% capacity, at nearly 647,000 acre feet, at an elevation of about 464 feet. At Oroville Dam on the Sacramento River, storage levels have fallen, but the dam is still at 2.9 million acre feet, or 82% of capacity.
Shasta Dam near Redding also was at 80% of capacity at 3.6 million acre feet on Monday. Bullards Bar Reservoir on the Yuba River near Dobbins in the Yuba County foothills was at 83% of its 966,000 acre-foot capacity, at about 806,200 acre feet, according to the California Department of Water Resources.
North of Sacramento, the Tisdale Weir will reach monitor stage on Wednesday. Fremont Weir will hit monitor stage early Thursday, according to the California Nevada River Forecast Center.
Parade of storms
The region has been doused by 12 atmospheric river storms in three months. Friday, Gov. Gavin Newsom lifted drought measures – but not saying the drought is over.
“It would be nice to have a governor say that the drought is over,” Newsom said in a briefing beside flooded Yolo County wetlands. “But unfortunately, complication requires nuance.”
The drought’s long-term effects – such as the need to replenish groundwater drawn during the severe drought – will linger.
Water management officials also must wrestle with toggling between keeping the reservoir water levels high for the summer and releasing water to prevent flooding, as more rain and a growing snow pack can threaten a saturated valley.
That’s why eyes are once again on the Cosumnes River at Michigan Bar near Rancho Murieta. Its projected peak height of just above 7 feet at 3 a.m. Wednesday is solidly in monitor stage and well below the river’s 12-foot flood stage.
Downstream at the McConnell monitoring station, the Cosumnes will rise sharply with Tuesday’s storm from 30.8 feet Tuesday afternoon to an anticipated 37 feet at its 7 p.m. Wednesday peak. But the river will be just above the 36-foot monitor stage and below the 42 feet that signals flood stage.
The Sacramento region and Northern California could, however, get some relief this weekend as a weaker system is expected to veer north into Oregon, forecasters say.
