Evacuation plans, dam safety main priorities for Half Moon Bay

The city’s draft safety element document aims to address these concerns starting with high-level goals — for example, becoming a community where flooding no longer affects residents and businesses — all the way down to implementation actions, like updating the storm drain master plan.

The 56-page document is being put together as part of a larger Peninsula Resilience Effort among San Mateo County and eight participating cities, including Half Moon Bay, and addresses eight major safety topics, including flooding, fire, drought, shoreline hazards and emergency preparedness. 

While the draft safety element — which will move toward approval from state agencies by the end of 2025 to beginning of 2026 — touches on the fact that Half Moon Bay doesn’t have a standardized evacuation plan, councilmembers and planning commissioners alike struck that point home during a joint meeting Nov. 18. 

“Our number one risk strategy in Half Moon Bay, if an event ever happens, is run away. That’s literally the first thing we need to do, is run away,” Planning Commissioner Rick Hernandez said. “The last time we tried to run away, when we had a tsunami warning, we didn’t do it very well.” 

On Dec. 5, 2024, a 7.0 earthquake off the Humboldt County coast prompted a tsunami warning for coastside towns, with text messages from San Mateo County officials directing those in low-lying beach areas to move to higher ground and canceling evacuation and warning efforts when it became clear that there was no threat.

It would be prudent for the safety element to prioritize evacuation plan development and include considerations for where community members could shelter in place in the event that they can’t evacuate, Vice Mayor Debbie Ruddock said. 

“I think we should also consider where we might shelter in place safely, or as safely as possible,” she said. “Depending on the event, we might not be able to evacuate everybody as quickly as we need to.”

It would also be helpful for the community to develop safety strategies in the event that the Pilarcitos Dam and Reservoir ever failed, multiple councilmembers and commissioners said. 

“I’d love to see something where we have clear communication to the city about what the status of the Pilarcitos Dam and what mitigation we can take if and when that dam fails, because maybe there’s nothing we can do but run away,” Hernandez said. “We have clever people in our community — there may be things we can do and plan for.” 

Efforts to install a stream gauge on Pilarcitos Creek to provide early warning for dam inundation would be beneficial to include within the safety element, Ruddock said. 

Also at issue within the safety element was the potentially contrary advice it provides when protecting against different types of emergency events. For example, including wood chip mulch in landscaping might be good when dealing with droughts, but it’s terrible for protecting against fire hazards, Mayor Robert Brownstone said. 

“It’s really frustrating when you put people in those double binds,” he said. 

In the same vein, policies espoused by Cal Fire to remove trees in close proximity to properties — a strategy they may be enforcing with increased attention in the coming years — can also protect against fire, but have potentially harmful impacts to defending those same properties from flooding and runoff. 

“When we talk about fire mitigation, we’re talking about removing trees, but it affects what we do or how we create safe places for people, because now we’ve lost all the shade when it’s hot, we’re increasing runoff, we’re increasing the risk of flooding,” Hernandez said. 

Hernandez emphasized a holistic approach to safety measures that should take into account how different protective tactics impact all risk while defining what the city should focus on first.

“I want our little town to not float away, get washed away or burn to a crisp,” he said. “When we look at these policies, we need to have some prioritization of what we’re going to focus on.”