A tropical storm hasn’t made landfall in San Diego County since 1939, according to the National Weather Service. But late Sunday, Hurricane Hilary (which meteorologists predict will then be a tropical storm) is set to touch down in Southern California – and with it torrential rain.
“Potentially catastrophic flooding. Let me say that again: potentially catastrophic flooding,” said Jamie Rhome, deputy director of the National Hurricane Center. “If you got weekend plans, it’s probably time to start altering those plans.”
Mountain areas in the county could see anywhere from 4 to 6 inches of rain, while the rest of the county may get 2 to 4 inches over a five-day period. For context, San Diego International Airport received 5.14 inches of rain during the entire month of January – a period that saw excessive flooding across the city.
To help you get ready for Hilary, we’ve compiled a list of the five neighborhoods in San Diego most likely to flood.
Mission Valley

The Mission Valley area is San Diego’s crown jewel of flooding. The area’s flood prone nature is no surprise, after all, Mission Gorge and Mission Valley are major floodplains carved out by the San Diego river. During nearly every heavy rain event, reporters reliably gather to document drivers stuck in the river’s surging flow and the potential rescues that follow.
The development of these areas, wherein once porous land able to soak up more water was swapped out for concrete and asphalt, only heightened the issues. Still, despite the predictable seasonal flooding, regional leaders are ramping up to shell out billions to intensify development of this area and are assuring residents they have plans to deal with all the water.
The city of San Diego plans to place “no parking” signs in flood-risk areas and crossings near the San Diego River. The city also plans to have crews clean storm drains in the area.
San Ysidro/Tijuana River Valley

When the region was hit with a deluge of rain in January, San Ysidro’s Tijuana River Valley was hit hard. As it does basically every time it rains, the Tijuana River overflowed and ranchers in the Valley just north of the Mexican border watched as their properties were submerged with murky water. The experience left some ranchers wondering who was supposed to be maintaining the often-clogged channels. When photojournalist Ariana Drehsler visited again a week later, after much of the water had receded, the damage left behind was immense.
Otay Mesa
The history of catastrophic flooding in the Otay Mesa region dates back more than 100 years to the catastrophic “Great Flood of 1916.” The weeks-long January downpour, still one of the wettest periods in San Diego’s history, came after a devastating four-year drought that even spurred the city to hire rainmaker Charles Hatfield in 1915. The following year, several Pacific storms converged on San Diego and rains flooded the whole valley of Otay Mesa, destroying hundreds of farms and causing a wall of the Otay dam to break which killed nearly a dozen farmers living in its shadow.
These days, devoid of a rainmaker, Otay Mesa is subject to the same frequent Tijuana River flooding as its neighbor to the west San Ysidro and from Otay Lake that feeds into the Otay River that runs to the coast.
Southcrest
Southcrest, a community just north of National City has long seen devastating flooding when heavy rains come partly because of an abandoned freeway project turned into a park — and because of a severe lack of storm drains. Residents say their homes are submerged by flood water every time it rains, but the city has done nothing to abate the issue. That’s why in 2019, they sued the city for flood-related damages and for more drainage systems to prevent future flooding.
Carmel Valley
The community of Carmel Valley, just east of Del Mar, is another frequent victim of rain-related flooding. The lion’s share of the risk is on the community’s western edge, which borders the Torrey Pines Preserve and Los Peñasquitos Lagoon.
Across the County
The mountains and deserts could get the most rain from Hilary. The Union-Tribune reports that Julian and Borrego Springs could get 4 to 6 inches of rain. El Cajon and Ramona have experienced major floods in the past.
Managing editor Andrea Lopez-Villafaña contributed to this post.
You left out the obvious Mission and Pacific Beach. The storm drains are antiquated.
I think no matter where we all live in San Diego, there is a major threat of flooding. My street in Poway flooded a couple years ago just from rainfall where it came up on my driveway. Some ppl tried driving thru it & while a couple big trucks ended up being successful, other cars couldn’t make it. By looking at my street, you would never think it would flood, but this wasn’t the 1st or last time it flooded.