LIVE OAK — When a nearly 9-foot-tall bright white globe popped up on top of the Santa Cruz County Sheriff’s Office building last month, neighbors and Highway 1 commuters alike wondered, “Has that always been there?”
The facility is not, as some have playfully speculated on neighborhood social media sites such as Nextdoor, a public art project funded by traffic fines, the bottom ball of a snowman, the ball for an oversized game of pingpong, an outdoor shower ball or the potential canvas for a giant beach ball painting.
The highly visible fiberglass radome — the name for a protective radar housing — jackets a new more than $500,000 grant-funded rainfall monitoring system operated by the Santa Cruz County Flood Control Division. Inside the sphere is space enough for the X-band radar antenna to spin continuously, emitting microwave radio beams that will bounce back off the raindrops and other atmospheric particles countywide, once power is connected in the coming months. County officials also are hoping the new system will provide a process for identifying wildland fire smoke columns in the offseason, as similar Bay Area radars have done.
“Radar technology for monitoring weather is not new, but having these smaller, deployable, very high-resolution radars, it’s cutting-edge technology,” said Flood Control District Manager Mark Strudley from atop the Sheriff’s Office rooftop Friday. “There aren’t a lot of water resource agencies, flood control agencies, that have this in their quiver. They may have some gauges, but typically they don’t own their own radars.”
Weighing some 1,800 to 2,000 pounds, a crane was brought in to drop the rooftop radar structure in place Aug. 19.
The installation of the X-band Weather Radar System will improve emergency managers’ ability to track and respond to rainfall events and fires within about 30 miles in each direction of its location. In a time when drought conditions are more likely at the forefront of most residents’ thinking than flooding, Strudley said preparation for potential heavy rains is equally important.
“A big storm that can threaten our safety can come any year,” Strudley. “The example I gave earlier was the Jan. 4, 1982, storm that created Love Creek slide and flooding on the San Lorenzo and elsewhere. We can get freak large storms in very dry years. We had one last year that created a debris flow on Foreman Creek in the CZU burn scar.”
Boulder Creek Volunteer Fire Chief Mark Bingham said he was excited about the new technology’s potential applications. Most weather predictions for San Lorenzo Valley, he said, were “behind the curve and maybe not as accurate,” a significant hindrance in weather-related emergency response situations. Bingham said he was looking forward to more accurate real-time data, particularly related to heavy rainfall in the period of heightened debris flows after 2020’s CZU August Lightning Complex.
“We’re usually not well-represented when it comes to predictions. I’m not blaming a person or the technology — I don’t know why,” Bingham said. “We take the data from the best possible sources, which is the National Weather Service and local knowledge. But we would be better served if we had some new technology like that one … allowing us to have a better response plan.”
The purchase of the radar system was made possible back in 2018, after the Flood Control Division was awarded a more than $725,000 state Department of Water Resources grant for the facility’s purchase and installation. The system’s cost has come in under budget to date, according to Strudley, but costs for the radar’s supportive structures and setup have not yet been fully calculated, he said. Delays to the system’s arrival spanned location siting, the outbreak of the coronavirus pandemic and the August 2020 CZU August Lightning Complex fires, Strudley said.
After it has been calibrated for accuracy during the remainder of this year, Santa Cruz’s radar data will be shared with local emergency response agencies, as well as with the National Weather Service and partners from the National Oceanic and Atmospheric Administration in Colorado, and, eventually, the public via the county’s santacruz.onerain.com. A larger Bay Area system of similar grant-funded radar installations is in the works, as well, which will help pass information to a larger area, Strudley said.
“It has been my experience supporting law and fire and emergency managers that they’re often asking the questions of, ‘We’re in the storm now, where do we need to position our limited resources,’” Strudley said. “So, this tool helps us advise them on where to position their efforts and resources because we’ll know with more specificity where those targeted areas are in a given storm.
Already, a larger version of the radar — the National Weather Service’s larger “Nexrad” Doppler radar station — sits on Mount Umunhum in the Santa Cruz Mountains. When it comes to pinpointing “microclimate” weather forecasts in Santa Cruz County and beyond, however, that radar struggles to detect rainfall below its approximately 3,500-foot-elevation. Santa Cruz County and U.S. Geological Survey also operate respective networks of river and stream gauges, while the cities of Watsonville and Santa Cruz feed in data from their water-level sensors — data that offers pinpoint location data, but not a more comprehensive picture, Strudley said.
“We’ve been having these atmospheric rivers, ‘Pineapple Expresses,’ come in — these very narrow bands of intense moisture,” Strudley said. “When we have forecasts for those, for example, the Weather Service will often provide information that says, well, our best guess is this train of moisture is going to make landfall somewhere between Santa Cruz County and northern Monterey County, but we don’t know where.”
“This (radar) spins around faster, so it can update quicker,” Strudley added. “So, it can get us updates within a couple of minutes. What’s the current rainfall pattern look like? And that matters, sometimes. With the really flashy storms and flashy creeks we have around here, things can happen really quick.”
Strudley tells a story of being out last year with his staff members, installing a new rain gauge upslope of the coastal Cascade Ranch, which is adjacent to Big Basin Redwoods State Park. The Weather Service radar showed clear skies, even while it poured so hard that the group needed to have their vehicles towed out of the resulting mud.
Atmospheric rivers “wriggle around like a firehose,” Strudley said, one type of highly unpredictable weather condition where the new radar will “really help” with short-term forecast warnings.
One X-band radar system early adopter was the Pajaro Valley Water Management Agency, whose board voted in 2018 to lend financial support to the radar project. General Manager Brian Lockwood said the water agency was aware of its potential benefit for the ongoing College Lake Integrated Resources Management Project. While not a flood control project, College Lake will store rainfall runoff. In the dry season, the agency will be able to raise a type of small dam barrier known as a weir to increase water capture capabilities. A problem arises when the reservoir is near to capacity and unexpected heavy rains are on the way.
“We don’t want to find ourselves in the situation when the weir is up and we’re near capacity and a storm event’s going to come through and could potentially lead to any kind of flooding,” Lockwood said. “Having X-band radar locally, I think it’s going to help for a lot of reasons. It’s just going to improve our understanding of atmospheric events, how the weather affects us, here on the Central Coast.”
