Flood problems grow on central coast as new storm approaches

A dam breach on a storm-filled river on California’s Central Coast quadrupled, complicating repairs on Monday and spilling floodwaters into farmland and farming communities – even as another atmospheric river has targeted the wetland state.

A dam breach on the Paharo River rose to at least 400 feet (120 meters) after it failed late Friday night, officials said. More than 8,500 people were forced to evacuate, and about 50 people had to be rescued due to rising waters.

Built in the late 1940s to protect against floods, the dam has been a known risk for decades as there were several breaches in the 1990s. In January, an emergency repair of the berm section was carried out. The $400 million renovation is due to begin in 2025.

The river separates Santa Cruz and Monterey counties, about 70 miles (110 km) south of San Francisco.

Monterey County officials also warned that the Salinas River could cause significant flooding of roads and farmland, cutting off the Monterey Peninsula from the rest of the county. The city of Monterey and other communities are located on the peninsula.

Forecasters have warned of more flooding, wind damage and potential power outages from a new atmospheric river that is expected to arrive Monday evening in the northern and central part of the state and move south within a few days.

The massive plume of moisture from the Pacific Ocean extended almost to Hawaii.

“Avoid unnecessary travel and complete all preparations as soon as possible,” the San Francisco Meteorological Bureau said.

California has already been hit by 10 atmospheric rivers this winter, most recently from a system that collapsed last week, as well as arctic air storms that have reached blizzard status.

Gov. Gavin Newsom declared a state of emergency for six more counties on Sunday after earlier making statements for 34 counties.

The atmospheric river last week carried warm subtropical moisture that caused the lower elevations of California’s Sierra Nevada snowpack to melt, increasing runoff that caused rivers and streams to swell.

But the snowpack is so deep and cold that it has mostly absorbed the rain, leading to more snowpack in the southern and central Sierra, said Daniel Swain, a climatologist at the University of California, Los Angeles.

Online data from the California Department of Water Resources showed on Monday that the water content of the Sierra’s snowpack was 207% of the April 1 average, when it is normally at its peak. In the southern part of the Sierra, it was 248% of the average.

According to Swain, the incoming atmospheric river will not be as warm as the previous one because there is cold air at its back.

According to him, even if it is not an extremely atmospheric river, its rains will fall on oversaturated soils.

“That’s why I’m more worried about this than the previous one,” he said.