A series of storms brought rainfall across the Bay Area last weekend, raising concerns about localized flooding and leading to several San José-based events to be postponed or canceled.

Craig Clements, director of the Wildfire Interdisciplinary Research Center at San José State and a professor of meteorology, said there has been a series of late season cold fronts moving through the region that are associated with lots of clouds and precipitation.  

“Springtime showers are nothing out of the ordinary,” Clements said. “We usually get a few late season storms (that) move through Northern California in April.”

San José received approximately 0.7 inches of rain from April 10-12, according to a San Francisco Chronicle article. 

The storm system affected much of the Bay Area, bringing steady rain and some occasional heavier precipitation bursts through Saturday and Sunday and while not extreme, the rainfall was enough to raise concerns about localized flooding and thunderstorms, according to a National Weather Service forecast.

Roger Gass, a meteorologist from the National Weather Service’s Monterey location, said the storm was well forecast. 

“We’ve been sending out partner email briefings to emergency managers and the media for several days ahead of the storm system,” Gass said. “The amount of rain was a little bit more than what we had originally forecast, but it still panned out pretty much the way we anticipated.”

With the storm forecasted well in advance, some events chose to cancel many days beforehand, including San José Made’s “Little Shops Village” event that was planned for April 11-12. 

On April 8, the event was canceled because of inclement weather, mentioning rain and cold temperatures, according to its Instagram post.

“It wasn’t necessary for events to be canceled,” Clements said. “It will be wet, cold and windy mostly, but there is a chance of thunderstorms to develop and so being aware of lightning risk is important.”

Other events were postponed the day of, such as the SJSU women’s tennis team’s Sunday match against the University of Nevada, Reno that was postponed to Monday, according to the Nevada Wolf Pack page.

The Adopt-a-Storm Drain Earth Month event was also canceled this weekend, which was going to be held by the City of San José’s Environmental Services Department, where the event was scheduled to take place at Penitencia Creek Park on Saturday from 10 a.m. to noon, according to a City of San José media advisory.

Carlos Velazquez, public informational manager of San José’s Environmental Services Department, said the threat of rainy and muddy conditions at the event location is what prompted a postponement of the event.

“A new date has not been set yet,” Velazquez said. 

The event was supposed to help community members learn about and sign up for the Adopt-a-Storm Drain program, which included a walk to Penitencia Creek with a presentation on watersheds, a storm drain cleanup demonstration and an information session with Peninsula Humane Society & SPCA, according to Velazquez.

Storm drains carry rainwater and runoff directly into local waterways without treatment, according to Clean California.

 During rainy conditions, that runoff can also contribute to flooding and unsanitary conditions if drains are blocked.

After learning how to properly clean a storm drain, volunteers would have been given the chance to name their own storm drains. 

“Some of our favorites include: Drainbow Connection, Drain-o-saurus Rex, Drain Teaser, Drain Damage and Drain “The Rock” Johnson,” Velazquez said.

The Adopt-a-Storm Drain program was first launched on Earth Day 2024 and has expanded to include more than 100 residents, schools and community groups, according to the media advisory. 

“Events like these raise awareness about stormwater runoff and the important role that residents can play in reducing water pollution and preventing flooding by making sure only rain goes down the drain,” Velazquez said. 

Storm drains in San José are part of a much larger watershed system, with around 35,000 inlets across the city that carry runoff into local creeks and rivers, which eventually flow into the San Francisco Bay, according to the City of San José.

Keeping storm drains clean is an important part of weather safety and can help prevent flooding or pollution, according to the City of San José.

“Trash, debris and pollutants that enter our local creeks and rivers ultimately flow untreated to the Bay, impacting water quality, harming wildlife and potentially hindering flood control protection,” Velazquez said.

The National Weather Service website provides safety tips and resources on what to do in a flood, as flash flooding can start within minutes, according to a National Weather Service webpage.

“If there’s water on the roadway, we always say ‘turn around, don’t drown’,” Gass said. “Especially at nighttime, where you don’t know if the road is washed out underneath the roadway.”