NBC Bay Area's Stephanie Chuang reports from San Jose on how the rain caught many people off guard.
The last day of summer went off with a splash across the Bay Area as heavy downpours ruined outdoor plans for thousands.
The rain started in the North Bay and crept south throughout the morning and into the afternoon. By dinner time, the system had moved on with clear skies above.
NBC Bay Area meteorologist Rob Mayeda said he saw quite a few records washed away by rain totals exceeding half an inch.
"The totals are more impressive when you realize not only did these numbers break daily rainfall records, but in some cases exceeded the September average for monthly rain totals," Mayeda said.
Here are the rain totals as of 4 p.m.
The impact of all that water was felt in all regions.
It is the first real wet weather to hit the Bay Area. It was a very dry spring, and the summer had few drizzles.
The Oakland A's game was delayed by more than two hours. The America's Cup race was canceled on the San Francisco Bay and the region-wide coastal cleanup was a wet and soggy one.
That is not to mention the dozens of soccer games, birthday parties and other outdoor activities that were planned this Saturday.
The threat of rain did not stop Keith Urban fans from attending his concert tonight at Shoreline Amphitheatre in Sunnyvale.
Danielle Bustamante, who came from a rainy Central Valley, said she made the 90-mile drive to the concert even with the rain on her mind.
"It rained pretty hard, so we were wondering if this was going to be canceled," Bustamante said.
Just in case, Bustamante said she came bundled up and ready with an umbrella.
"I didn't expect it," she said. "I was taken by surprise. I didn't prepare. I actually borrowed this [blanket] from my mother-in-law."
On the roadways, the CHP reported a big increase in collisions.
The CHP said there were more than 3,000 calls to its dispatch center Saturday compared to a normal weekend day which would have had less than 2,000 calls in the same time period.
One accident of note comes from our morning traffic reporter Mike Inouye. He says a pickup crashed in Oakland on northbound 880 near the 29th Avenue exit. The truck spilled a trailer filled with dry concrete mix. The rain turned the mix into real concrete. It took a jack-hammer and real muscle to clean it up. Traffic backed up from Decoto Road in Fremont to 29th Avenue in Oakland.
In another accident, investigators said a man driving a jeep lost control, causing a big rig to jack knife.
"It hasn't rained for months now...extremely slick...," CHP officer Nenad Gorenec said. "I advise everyone to slow down way more than they even think they should."
In the South Bay, a cargo truck and two cars were involved in an accident on 101 in Mountain View Saturday afternoon. No one was seriously hurt.
The rain and unfavorable wind conditions prompted the cancellation of Race 14 in the 34th America's Cup, which is now set for 1:15 p.m. Sunday.
Officials say that while winds today were too far west to make for a good course, good conditions are expected on Sunday.
The rain not only caused a delay of the A's game it caused a flooding.
Twins relief pitcher tweeted a photo of his visitors dugout covered in four inches of water.
He questioned whether it might be sewage.
Visitor dugout in Oakland. Probably 4" of standing water/potential sewage. pic.twitter.com/kAZGQx0cfr
— Glen Perkins (@glen_perkins) September 21, 2013
The rain turned to snow in Tahoe. Heavenly Mountain resort said while it is raining at lake level, it started to snow at the top of Dipper Express at 1:30 p.m.
They even sent a photo (see left).
The unusually high totals were due in part to an early season late October-style weather system sweeping a cold front into the Bay Area meeting up with warmer, higher moisture air in place from the south.
As the weather system lift increased with the frontal passage, rain accelerated higher in heavy downpours quickly changing over to sunshine and a few passing showers into the evening.
Mayeda says isolated showers should end by Sunday morning, with showers changing to snow in the Sierra near 7,500 ft overnight before clearing skies return in the high country for Sunday.
A much calmer weather pattern will take hold for the rest of the weekend as Fall begins in the Bay Area Sunday afternoon at 1:44 p.m. Though after today our rainy season is already off to an early, higher than average start for September.