You are now in San Diego County category.

Rainwater erosion alongside the Oroville Dam’s main spillway appears to have contributed to the heavy damage that prompted a crisis, forcing more than 100,000 to be evacuated from their homes, a report reviewed by The Times showed. A summary of the incident, prepared by state water officials four days after the crater in the concrete chute appeared, said water from heavy rains hit the hillsides where the massive concrete spillway runs. Flowing water during heavy rains was “diverted … effectively eroding and undermining the spillway, causing a section to collapse,” said the incident summary.

Good morning. It’s Thursday, Feb. 16, and here’s what’s happening across California: TOP STORIES Will Oroville hold? Tons of rain will be dumped on Northern California this week, but state officials are confident that this inclement weather won’t break the Oroville Dam or its damaged spillways. “It’s holding up really well,” said Bill Croyle, acting director of the state Department of Water Resources.

Eastern Municipal Water District dropped most water restrictions Wednesday – moving from measures taken to meet the state’s mandatory conservation orders to encouraging voluntary savings among customers. While state bans on wasteful water use remain, the district board voted unanimously to end its own restrictions and return the water rate structure to pre-drought emergency order levels after supplies increased following heavy rain and snowfall, especially in Northern California. Western Riverside County remains in a moderate drought.

What is most surprising about the near-collapse of a spillway at Oroville Dam is that events like that have not happened more often. Located 75 miles north of Sacramento, Oroville is the nation’s tallest dam and holds back the state’s second-largest reservoir. Both its main spillway and an auxiliary one have experienced major erosion because of massive emergency releases of reservoir water during this winter’s heavy storms. On Sunday, engineers worried that the top 20 or 30 feet of the emergency spillway could give way, causing devastating flooding on the Feather River.

A powerful new storm is expected to arrive in Southern California on Friday, and it could provide a walloping, with possible flash flooding, mudslides and rock slides. “The Friday storm in particular could in fact become the strongest of the season in the Los Angeles region,” said UCLA climate scientist Daniel Swain.