As city and county employees work to fortify berms along San Diego beaches, crews are also busy preparing popular hiking trails and protected inland areas for the possibility of flooding and rockslides during what could be a historically wet winter.
At the city level, officials are also concerned with the impact that heavy rains could have on bridges and park facilities, according to city spokesperson Benjamin Cartwright.
“City staff have been proactive in clearing out and removing accumulated leaf litter, debris, soil build-up and trash from drains around the park’s facilities and surrounding areas, reducing the risk of potential flooding,” Cartwright stated in an email to Times of San Diego.
Crews will have to navigate different types of issues based on San Diego’s diverse topography. Spaces like Mission Trails, Cowles Mountain or the Los Peñasquitos Canyon Preserve face different potential scenarios for El Niño.
In Mission Trails, the hilly areas could see trail erosion, hillside movements and rocks shifting over water-saturated soil.
For higher peaks such as Cowles Mountain, those spaces could experience rockfall and rockslides. City crews have worked to improve existing drains and add new ones on steeper trails like Cowles Mountain, Cartwright said.
As for Peñasquitos Canyon and other low-lying areas, a wet winter could mean increased chances of flooding during El Niño. These spaces have what Cartwright describes as “flashy flows” – streams and creeks that rise rapidly following a rainstorm.
According to county spokesperson Donna Durckel, it can take time for this type of area to recover.
“After heavy rains and back-to-back storms, some of these low-lying areas can remain inaccessible for several weeks,” Durckel stated in an email to Times of San Diego.
Crews must also address unstable ground conditions from fire damage, such as in Peñasquitos Canyon, which suffered two major fires in June and August 2026. In total, 230 acres burned this summer.
“Any burn scar area should be managed to prevent erosion and control runoff using best practices such as sandbags, fiber rolls and mulch,” Durckel added.
The San Diego county’s Department of Parks and Recreation is also inspecting drainage infrastructure, securing loose signs and equipment, verifying emergency access routes, checking water and septic systems, pre-positioning caution signs and monitoring weather forecasts.
Daniel Swain, a climate scientist specializing in the impacts of extreme weather events and global warming, wrote about El Niño’s record intensity in the weather blog, Weather West.
“Quite frankly, I’ve never seen anything like it before (and I do not say that lightly),” Swain wrote in an Oct. 12 blog post.
Swain forecasts El Niño to peak sometime in December and to last until March.
Swain estimates a 90% chance southern California will experience a wetter-than-average winter.
County spokesperson Durckel said county residents can visit alertsandiego.org to find resources to prepare for the upcoming El Niño, such as how to build an emergency kit and register for emergency alerts.
City spokesperson Cartwright recommends residents stay alert when enjoying the outdoors this winter.
“Rainfall events, like the ones anticipated with this season’s El Niño, can make park and trail conditions suddenly hazardous,” Cartwright said. “Recreators should always check the weather before embarking on any outdoor activity, call ahead for updated condition reports and refrain from utilizing open space areas during any expected storms.”
