SANTA CRUZ — All Santa Cruz County debris flow evacuation orders were reduced to warnings as of Thursday, according to Cal Fire San Mateo – Santa Cruz Unit Chief Ian Larkin.

“Every zone is being reduced to a warning, we’re allowing everyone to return home,” Larkin said. “We’re going to keep it at a warning through the weekend to keep people on alert, they shouldn’t unpack everything yet, just to make sure we don’t have a system come in that would make us make a different decision.”

The reason for the downgrade? The atmospheric river system, which particularly posed a debris flow risk to CZU Lightning Complex fire-scarred areas, has decreased in severity and is migrating away from Santa Cruz.

Brayden Murdock, a meteorologist with the National Weather Service, said the forecast shows the storm leaving Santa Cruz early Friday morning.

“This is still kind of the remnant of it, but it’s lost a lot of its strength and we’re not going to see those really heavy rainfall rates,” Murdock said.

From 5 p.m. Wednesday to 5 a.m. Thursday, the agency documented up to 1.5 inches of rain dropping across coastal Santa Cruz and up to 2.5 inches falling in the Santa Cruz Mountains.

“After talking with the National Weather Service and seeing that this storm is starting to be on the tail end … that we don’t expect thunder or an atmospheric river to develop … and in consultation with the county geologist, we’ve determined that the potential has reduced enough for us to allow people to go back to their homes,” Larkin said.

The Cal Fire chief compared how the event unfolded in the Santa Cruz Mountains, to Monterey County, where residents near the River Fire burn scar suffered home damage.

“The key element is, we dodged a bullet here, and in light of what occurred in Monterey County … this was a precursor to what could happen in the future as we get storms that come in with atmospheric rivers, which dump a lot of moisture over a short period of time,” Larkin said.

Rainfall rates were documented across Santa Cruz County that met risk thresholds this week, but no major debris flows have been reported.

The National Weather Service recorded two local sites exceeding those thresholds during Wednesday’s storm: during the early morning hours Ben Lomond saw 0.76 inches of rain falling, according to the agency.

For that same 1-2 a.m. time period Wednesday, the agency documented a site off of Empire Grade, west of Ben Lomond Mountain, collecting 0.83 inches of rainfall.

According to current benchmarks established by the county, 0.7 inches of rainfall occurring over an hour period could present debris flow risk in burn scar areas.

On Thursday, upon returning from field inspections, County Geologist Jeff Nolan told the Sentinel that beyond typical winter storm impacts — muddy creeks, small landslides, plugged culverts — no major movements have been observed.

Santa Cruz County Public Works crews will be clearing ditches, roadways and culverts of minor debris and other blockages in the coming days, according to Department Director Matt Machado.

“I would say we’re pretty fortunate to have weathered it with such minor issues, but I don’t think that we can assume that for the next time. So we have to be in a state of readiness,” Machado said at a press conference Thursday.

When asked if debris flow risk-thresholds — which triggered this week’s round of evacuations — would be amended, Machado said that will depend on evidence collected by Nolan and other geologists in the coming days.

“If we can find evidence to make adjustments, we will,” Machado said.

County Communications Manager Jason Hoppin said county officials and scientist partners, would review what occurred during this week’s weather event in an “after action assessment.”

“We set those thresholds based on input from experts, the weather service, the experience of other counties, and our own data about our soils. But there’s no teacher like experience, right? So we’ll all get together and talk about that,” Hoppin said.

Remaining resources

Santa Cruz County officials are urging residents who see any evidence of debris flows on their property to email firerecovery@santacruzcounty.us. As of Thursday morning, the county had closed all temporary evacuation shelters they operated in conjunction with the Red Cross.

The county’s call center will remain open until Thursday afternoon for those who may need information on evacuation notices, call 831-454-2181.

The Santa Cruz County Sheriff’s office will continue to have increased deputy presence in the San Lorenzo Valley throughout Thursday evening, according to Chief Deputy Chris Clark.

“Frankly, we got lucky,” Clark said during a press conference Thursday. “I’m extremely happy that nothing happened.”