Debris flow evacuation orders stay in place for Santa Cruz Mountains with storm shift

Santa Cruz Sentinel (CA)

Jan. 27—SANTA CRUZ — Rainstorms continued to threaten fire-scarred areas of Santa Cruz through Wednesday, as some 5,000 local evacuees remained under notice.

An atmospheric river storm, according to National Weather Service officials, had already made landfall in parts of Santa Cruz County as of Wednesday afternoon, and poses a heightened debris flow risk to CZU Lightning Complex fire burn scar areas into Thursday morning.

These storms can mean high rates of rainfall occurring over a short period of time, which presents a risk of triggering debris flows.

"When you have a lot of warm, moist air meeting cooler areas, as soon as they interact it just turns to rain," Brayden Murdock a meteorologist with the National Weather Service said. "Basically if you're taking a fire hose and just putting it over one spot in your yard, its going to flood pretty quickly."

As of 3:30 p.m., the National Weather Service forecast that this storm would result in around an additional 2 inches of rainfall in the Santa Cruz Mountains over the course of Wednesday evening.

"We do have good idea it wont be there [Santa Cruz Mountains] for very long, but when you start seeing these rainfall rates high like that, it doesn't take long to have a risky situation," Murdock said.

A Flash Flood Warning was also been issued for Santa Cruz County through 6:30 p.m. Wednesday.

Brian Garcia, a meteorologist with the National Weather Service, told the Sentinel that through at least the early hours of Wednesday evening, the storm could present hazardous conditions for burn scar areas.

"The next 30 —120 minutes is going to be a very very difficult time on the CZU burn scar area," Brian Garcia a meteorologist with the National Weather Service said.

The heaviest rains are forecast to move out of the Santa Cruz area by Thursday, or at latest sometime Friday, according to Garcia.When asked if the atmospheric river storm was previously forecast to hit Santa Cruz on Wednesday afternoon, Garcia said it was not.

"No, this was not expected the way it's happening right now, we were expecting this to remain a little further south, we did not expect it to lift this far, this fast," Garcia said.

Garcia said these rainfall rates could very well hit established debris flow thresholds in the Santa Cruz Mountains. Those who have not evacuated at this point are advised to heed warnings or orders now.

An atmospheric river has moved north over Santa Cruz County. Be extremely cautious, avoid travel if possible and seek alternate shelter if you are in a debris flow evacuation zone. https://t.co/s5GvnBLmyF. https://t.co/CNdO5EDYvK

— Santa Cruz County (@sccounty) January 27, 2021

"The main thing is to listen to your local officials, if there's a warning or order in place, it's for your safety it's not because we want to keep you out of your house. We want everybody to live to see another day," Garcia said.

Santa Cruz County Chief Deputy Chris Clark echoed Garcia in a press conference on Wednesday.

"The people remaining and choosing to make that decision to stay...I can't stress more...you need to be absolutely aware of the weather situation and know your options," Clark said.

At least 261 households, according to Santa Cruz County Sheriff officials, elected to not heed evacuation orders.

"Know how to get out. But again, things could change there, a tree could fall over a road, you could get trapped," Clark said. "I'd encourage you to continue to seek shelter elsewhere if you chose to stay, its just an extra layer of protection for you and your family and you wouldn't want anything to happen."

Residents in the Santa Cruz Mountains and North Coast will remain under evacuation orders and warnings at least through Wednesday night. All previous evacuation notices continue to stand.

"We were hoping for better weather and we absolutely empathize that for those that are displaced from their home, that you want to get back home," Clark said. "We want that to happen as well, but we want to make sure we are protecting everyone that lives in those areas, where a debris flow could endanger you and your family."

The same advice for residents in at-risk areas remains:

—KNOW YOUR ZONE: Visit the debris flow evacuation zone maps at community.zonehaven.com and memorize your zone ID.

—Make sure you are enrolled in the county's reverse 911 call system, Code Red, by visiting https://www.scr911.org/.

—Stay alert leading up to and during storms — monitor news online, on your phone, by listening to a weather radio, and through the county's social media channels.

—Pack a go-bag with your essentials such as water, food, important documents and ID's, should evacuations be ordered.

—Track local rainfall levels using One Rain santacruz.onerain.com.

—Track road closures using sccroadclosure.org and report road blockages at 831-477-3999.

—Stock up on batteries, should power go out, and radio communication be necessary.

—Call 831-477-3999 if you are confused about your evacuation status, or what resources are available to you.

Reflecting on Tuesday's storm

Over the course of the Tuesday evening rainstorm Santa Cruz County saw continue overnight, rainfall rates did indeed hit debris flow thresholds.

But County Geologist Jeff Nolan, who did field inspections throughout the Mountains on Tuesday, told the Sentinel that he didn't see evidence for debris flows as of Wednesday afternoon.

"We saw very little evidence of anything, it looked pretty much like a typical winter storm in the Santa Cruz Mountains," Nolan said.

Still, Nolan said with the incoming forecast, he and others were on high alert, and residents needed to be too.

South of Santa Cruz, some Salinas residents sustained damage as a result of Tuesday night's storm. Flooding and mudflows impacted areas near the River Fire burn scar on River Road.

MCRFD working with local property owners on damage assessment In the River Rd area. Thank you to all the local ranchers helping with heavy equipment needs. pic.twitter.com/9xcVPio9kT

— Mont. Co. Regional Fire (@mcrfd) January 27, 2021

Questions have arisen on the cumulative impact of multiple storms hitting fire-scarred areas: Noah Finnegan, a professor at UC Santa Cruz, who specializes in geomorphology research said debris flow risk increases as more water runs off a steep slope and cumulates.

As the second element of the atmospheric river storm rolled in Wednesday afternoon, Finnegan hypothesized that if similar levels of rain fell Wednesday night, over the same time period, rainfall may potentially present a higher debris flow risk.

"If we get the same rates tonight as compared to last night, it's likely posing more of a concern, because the ground is wet," Finnegan said.

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