A flash flood raged through historic Ellicott City on Sunday evening, sending residents and tourists scrambling for higher ground and sparking a massive response by rescuers.

Maryland Gov. Larry Hogan (R) declared a state of emergency in Howard County and huddled with emergency officials to assess the situation. No injuries were immediately reported, but officials said the damage could rival that of the devastating flood that occurred there in 2016.

The National Weather Service called the flooding an “extremely dangerous and potentially catastrophic situation” as the rains pounded the city Sunday evening. Amid the flooding, the Howard fire department warned people trapped on the city’s Main Street to climb to the second floors of buildings as they awaited rescue.

Officials said there were reports of collapsed buildings. Hundreds of rescuers had converged from as far away as Northern Virginia, officials said, and Howard opened an emergency operations center to manage its response.

BGE said late Sunday that there would likely be “extended outages” of gas and electricity service until infrastructure could be fully inspected and “in some cases rebuilt.”

Videos taken on Ellicott City’s Main Street show roiling brown water flowing down, carrying debris and trash. The water spilled into doors and windows and twisted traffic lights. Some people on Twitter reported seeing cars floating down streets.

Loretta Moran was returning with her husband to their house on Main Street from their son’s wedding the night before when they noticed the Tiber River was running extremely high. They parked their car in front of their house and soon noticed some of their tenants trapped on their house’s upper floors.

As they rushed across Main Street, the water went from a trickle at their feet to their knees.

Loretta, 64, and her husband, Tim, 66, led the eight stranded tenants — including a 2-year-old child — and a dog out through their back exit.

“We have a deck that goes into the woods, and we knew that was an escape route to Church Road,” she said.

The group of 10 then scrambled uphill through the woods toward the Castle Angelo, a castle-like home built in the 1830s into the rocks above Ellicott City, overlooking the Patapsco River.

“It was horrible,” Moran said of the scramble through the woods. “The ground was washing away beneath us.”

When she looked back, she said, she could see water as high as 15 feet. She saw workout equipment washing down the street, leading her to believe a gym had collapsed.

When she reached her son on the phone, the newlywed asked her why they had gotten out of the car.

“People don’t understand,” she said, on the verge of tears, “it happens so quickly.”

Abigail Conte, 19, was at the Bean Hollow coffee shop in the historic section of the city when the rain began Sunday afternoon. She said the staff announced they were closing around 3:45 because of a flood warning.

She left the shop and began to make her way to her car about a half-mile away.

“As I was walking outside, the street was becoming a river,” Conte said. She came to an intersection where it became too dangerous to continue. She eventually sought shelter at Cottage Antiques. She hunkered down in a back room, worried a telephone pole might fall on the shop and was trapped for hours.

She said she saw a garbage can and other detritus flowing down Main Street but nothing larger.

“It’s just flooded,” said a woman who answered the phone at A Journey From Junk. “I’m trying to work through my own panic attack.”

Before declaring a state of emergency, Hogan activated the state’s emergency response, which sends extra rescue personnel to the scene from various state agencies, said his spokeswoman Amelia Chasse.

“The governor sends his thoughts and deepest sympathies to those impacted, including residents and businesses in Ellicott City,” Chasse said.

Jeff Halverson, professor of meteorology at the University of Maryland Baltimore County and a contributor to the Capital Weather Gang, said the storm pattern had essentially stalled over Ellicott City, the same phenomenon that caused massive flooding in the city of Frederick two weeks ago.

“To say lightning strikes twice is basically what’s happening,” Halverson said.

He said the storm could drop 10 or so inches of rain total before it wound down. He said he thought the flooding could ultimately be worse than what was seen in Ellicott City in 2016. Howard County officials had estimated the damage from that flooding at at least $22.4 million.

Ellicott City sustained severe damage in a July 30, 2016, flash flood that killed two people. During that flooding, houses along Main Street shook as residents filmed the devastation out their windows. Some formed human chains to rescue those stranded in their cars as the rising waters roared through the historic downtown.

In the 2016 flooding, Joe Blevins, a father of three, was swept away as he climbed with his girlfriend from their flooding car. His body was spotted by a hiker the next morning on the shore of the Patapsco River. The body of another tourist, Jessica Watsula, was found near the Ilchester Bridge.

Martin Weil and Ovetta Wiggins contributed to this report.