Two people were found deceased Thursday morning inside a vehicle that became submerged in rapidly rising waters on a Millbrae Street, amid heavy rain.

A low-lying part of Millbrae — a portion of East Hillcrest Boulevard near Hemlock Avenue that dips below a railway bridge — became a hazardous scene early Thursday amid the latest rainstorm. As KPIX reports, the San Mateo County Sheriff’s Office said firefighters responded to the scene at 5:45 a.m. after receiving reports of severe flooding. Upon arriving, they found a man standing on the roof of a submerged vehicle near the underpass, and then saw that a second vehicle was also submerged.

"The fire department entered the water to rescue the person in the vehicle. While doing that they realized that there was a second vehicle in the water,” said Sheriff’s Detective Javier Acosta, in a statement to KPIX. "So after they rescued the first person, they tried to gain access to the vehicle in the water. However, the conditions changed rapidly and it became too dangerous for the responders. The water was rising very rapidly and they had to retreat."

Once firefighters were able to access the second submerged vehicle, they discovered two individuals deceased inside the car.

It's unclear whether the car had been trying to pass through rising waters at the time — an image of the road from Google Streetview shows that there is no shoulder for parking in the area of the underpass.

East Hillcrest Boulevard in Millbrae, where two submerged vehicles were found. Photo: Google

Flooding has been reported in multiple locations around San Mateo County following the latest storm, but Millbrae appears to be particularly hard hit.

Images on Twitter from NBC Bay Area and ABC 7's Amy Hollyfield show significant flooding around Millbrae. And Cal Fire said earlier today, "We are responding to multiple flooding calls across the coastal area in San Mateo County."