Shortly before 10 Sunday morning, Clarence W. Nicholson and his 11-year-old daughter left the family home in Southeast Washington, slid into a compact car and set off on the weekly three-mile drive to church.

A half-mile away, 31-year-old William A. Powell started up his 1970 Cadillac and headed for a downtown methadone clinic where he had been undergoing treatment for four weeks.

A few minutes later, Powell's crumpled car would rest in the middle of Second Street directly behind the Nicholson car, now crushed to half its length by the force of a violent rear-end collision. Powell would be uninjured, police said, but a critically injured Nicholson would be standing helplessly beside his burning compact, screaming for help to rescue his daughter.

Eleven-year-old Melanie Nicholson, who dreamed of becoming a heart surgeon, would be dead, burned to death in the fiery collision.

"It happened so fast," recalled Betty P. Smith, the driver of one of the four cars stopped at a red light at Massachusetts Avenue and 2nd Street NW. There was no screeching of tires, no blaring horns, she said. In fact, there was no warning at all.

Just sharp, explosive impact. And fire.

"I just jumped out of my car and I saw this man Nicholson trapped . . . ," she said. "I saw his feet kicking at the window and then he got out somehow . . . He was hollering, 'Somebody get my baby out!' He was just yelling, 'Please get my child out of there.' "

Just how the Nicholsons and Powell, who has been charged with manslaughter in Melanie's death, came to that intersection at the same time is a story of routines.

Nicholson, 42, an office furniture salesman who is a deacon at the Corinthian Baptist Church at Fifth and I streets NW, liked to leave for church early so he could lead the church youth choir in prayers before the service began, said Clifford E. Winbush, chairman of the church trustees.

Melanie, a member of the junior choir and one of three daughters, went with her father as always, according to Machell Nicholson, Melanie's oldest sister. As father and daughter left the well kept, one-story home at 1711 30th St. SE in Randle Highlands, Melanie wore a black blazer and gray skirt and sported a new flip-style hairdo.

Melanie was carrying in her pocket the speech that she had been practicing for delivery at a Friday service where she was to be the master of ceremonies for a celebration of the church's 62nd anniversary, according to Machell, a 20-year-old junior at Catholic University.

Nicholson's wife Lois, a D.C. public school music teacher who played the organ and piano for the church, did not accompany them, Machell said.

Nicholson followed the regular route, driving to the Suitland Parkway, then leaving it and crossing the Frederick Douglass Bridge toward downtown. There he took the Third Street tunnel and exited at the ramp at Second Street where there were at least three cars in front of him when he pulled to a stop. They were just a few blocks from church.

It was to be an unexceptional Sunday for the Powell family as well, recalled Powell's wife Rose yesterday. She said that her husband, a part-time custodian, planned to be home about noon in time for Sunday dinner with the couple's three children and the Redskins football game on television.

About 10 a.m., she said, Powell left the fourth-floor apartment at 2304 Hartford St. SE for the trip to a methadone clinic on G Street. He had been visiting it for about four weeks, she said.

Shortly thereafter, according to police, a D.C. police radar clocked a Cadillactraveling about 80 mph on the parkway, where speeds are restricted to 30 and 45 mph. Officer James Harding in car 418 gave chase and was soon joined in pursuit by a second car, police said.

Harding radioed the police communications center, where standard procedure in a high-speed chase is to set up a roadblock, according to police spokesman Lt. Hiram Brewton. But one policeman said there apparently was not time enough to do so in this case.

Within moments, the Cadillac collided with the Nicholson compact which burst into flames instantly and set off a chain-reaction collision that left five cars damaged and four others injured, police and bystanders said. Neither the badly injured Nicholson nor police and fire rescue personnel were able to pull Melanie Nicholson from the crushed body of the burning car.

Yesterday, the two surviving sisters sat on a couch in the family's living room beneath photographs of the three sisters.

"She'd just wrote to me last week to tell me she'd gotten all A's and one B," said Malitta, 17, a freshman at the University of Virginia. Melanie was proud of the A's she'd earned in the sixth grade at Immaculata-Dunblane school, Malitta said, and promised she'd try to make it all A's next time.

Ever since the sisters could remember, the youngest sister had been determined to be a heart surgeon. "Anything that could give her a real challenge, she tried it," said Machell. The challenge lately had involved Melanie trying to juggle her academic goals with other pursuits, including soccer, basketball and piano.

"She was just so active . . . ," said Malitta, her voice trailing off.