At the end of an arid August, Sligo Creek trickles sluggishly from Silver Spring into Takoma Park. But on a hot August night in 1969, a violent thunderstorm swept through the area, and the usually docile creek turned into a torrent of water, cresting over the bridge on New Hampshire Avenue and submerging cars within minutes.

The Knowles family, of Woodbridge, had just turned off New Hampshire onto Sligo Creek Parkway, when the water rushed out of the creek, washing up past the door handles of the family car. In the ensuing rescue, which ultimately saved Ronald Knowles, his wife and their 3-year-old son Clark, two firefighters were killed, the only firefighters from the Chillum-Adelphi Fire House to ever die on the job.

For Robert Jacobs, who drove the fire truck that night, the incident retains an almost documentary-like immediacy. He still sees the firefighters' strobe lit by flashes of lightning as they swam through five-foot swells to reach the family clinging to the railing at the top of the bridge. He cannot forget the sickening crash of concrete as part of New Hampshire Avenue beyond the bridge gave way, pulling volunteer firefighters Robert Harmon Jr. and Robert Hobstetter down into the creek.

Each year around the time of the anniversary of the drownings, Jacobs, 67, places a wreath at a small bronze commemorative plaque next to Sligo Creek.

"I do it to keep the memory alive. I think it's important to remember those we've lost," said Jacobs, who has volunteered with the department for 41 years.

Jacobs has organized several memorial services for the firefighters, the most recent in 1990. He serves as the unofficial historian of the fire department, with a file of yellowing news clippings and a photo album filled with pictures from the memorial service. About 10 years ago, while in London, he met with Hobstetter's daughter Diana, who was living there at the time. She was 5 when her father, a technician for television station WTTG who lived in Bowie, died at age 31.

"I wanted to tell her about her father, about who he was and why he died," he said.

Colin Turner, then 18, was also at the scene that August night. He arrived from his Takoma Park house about a quarter mile away and perched on top of a street sign. Ronald Knowles escaped his car by opening a window, Turner recalled.

"I went into the water and got {the wife and child} out to the bridge," said Turner, 47, who now lives in Crofton. But then the road collapsed, sending Turner and the firefighters down into the rushing creek.

"There was no time to think. It was like a big drain. We were just sucked in," Turner said. "I was lucky. I wasn't wearing boots or equipment. My friends thought I was history, but I managed to grab a branch on the bank."

But firefighter Harmon, 23, a National Institutes of Health employee who had lived at the firehouse, was tethered to a rope, in which he became entangled under water. Hobstetter also drowned.

"I was just out of it for a few weeks. I felt so bad for those guys," said Turner, who received a $500 reward from the Carnegie Hero Fund for his efforts. Harmon and Hobstetter were honored posthumously.

Takoma Park firefighters rescued the Knowles family, who still clung to the bridge railing. Members of the Knowles family and relatives of the firefighters could not be located for this report.

For William Radisch, 74, of Calvert County, who was deputy fire chief for the Chillum-Adelphi Fire House, details of the incident now are vague, but the night still haunts him.

"The water was getting higher and higher every minute. And then we lost those two young fellows." He pauses and sighs. "For a long period of time it was hard for me. It's still difficult sometimes." CAPTION: Above, Colin Turner, left, and Robert Jacobs stand by memorial to firefighters who drowned in 1969 flood. At left, the two recall incident at the site. CAPTION: Robert Jacobs, right, of the Chillum-Adelphi Fire Department, and Colin Turner recall night two firefighters drowned.