A woman was critically injured and numerous other spectators sustained minor injuries yesterday when lightning struck Robert F. Kennedy Memorial Stadium in the middle of the huge Tibetan Freedom Concert, forcing promoters to cut short the first day of the show as heavy rains pelted the stage and stands.

"The top of my head felt like it was on fire," said Scott Shirley, 37, of Rockville, one of those who received minor injuries when the storm hit about 3:40 p.m. "I'm sitting here listening to Herbie Hancock, and all of a sudden I heard an explosion, and I woke up and it was as if they'd turned off all the lights in the stadium."

Tiffani Vannoy, 16, of Manassas, said she initially "blacked out" when struck by a lightning bolt. "I felt a shock through my legs. My legs were tingly. I was stumbling around because I was dizzy. I was 10 feet away {from those most seriously injured}. I count my blessings that it wasn't me."

"People were just scattering everywhere you can imagine," said D.C. Fire Battalion Chief William J. Gross.

The second day of the concert is to take place as scheduled today. Promoters said there would be no refunds for the 66,000 who attended yesterday's abbreviated show.

{Meanwhile, more than 100,000 homes lost power from storms in the area. Details on Page B1.} Despite the lightning, which sounded like an explosion when it hit the RFK stands, and the immediate suspension of the concert, thousands of fans waited in the rain, playing pickup football games on the field. Many even did "the wave" around the stadium five times -- hoping the concert would resume so they could see Tracy Chapman, Sonic Youth, Red Hot Chili Peppers, R.E.M., Beck and Radiohead, who had yet to perform.

But an hour later, Michael Stipe, R.E.M.'s popular lead singer, walked onstage and announced that the event was over for the day. A huge groan echoed through the crowd. Organizers expect that at least some of the performances that were canceled yesterday will be added to today's concert, which begins at noon and runs until 7:30 p.m.

Yesterday, the stadium was cleared by 5:45 p.m., more than two hours before the concert was originally scheduled to end. The field was littered with empty water bottles, blankets, clothes and shoes. Hundreds of young concertgoers lined up at pay telephones trying to call their parents to tell them they were not injured, but stadium workers shooed them outside and locked the gates. Parents, meanwhile, deluged D.C. General Hospital a block away with frantic calls trying to learn whether their children were among the injured.

What made the day's events particularly chaotic was the size of the crowd. The Tibetan Freedom Concert is the second-largest benefit concert in history, and organizers had sold 66,000 tickets for yesterday's concert and 66,000 for today's performances.

Only Live Aid, the 1985 concert staged simultaneously in Philadelphia and London to benefit famine victims in Africa, was larger than this weekend's event. It drew a total of 150,000 in both cities.

Donna Lewis-Johnson, a spokeswoman for D.C. General Hospital, said that doctors there had treated four patients. The most seriously injured was Lysa Selfon, 25, a law student at George Washington University. Selfon, breathing with the aid of a ventilator, was moved last night to Washington Hospital Center, where she was in critical but stable condition with severe burns on her face and body.

A friend who was at Selfon's side when she was struck said there was nothing concert organizers could reasonably have done to prevent the accident.

"This was a natural disaster," said the friend, who declined to give her name. "The lightning struck before the weather got bad. . . . It was not raining yet."

Also treated were Richard Smith, 50, of Columbia, and Loren Hall, 17, of York, Pa. A fourth victim was examined and released after reporting a tingling sensation in his arm.

Dennis Brown, of Baltimore, a friend of Smith's, said his group was sitting in Section 111, Row 5, Seats 1,2,3 of the stadium, near the dugout area of the 50-yard line, when the storm hit.

Smith, Brown said, lurched over. "It sounded like a bomb went off to me," Brown said. "The ground shook. Everything just shook."

Battalion chief Gross said the lightning struck five minutes after the department received a report that a violent storm was rapidly approaching. "We had reports it was going to come in 15 minutes," he said. "In five minutes tops, we got sent out for this."

Gross said each of the stadium's three levels had three or four aid stations set up with emergency medical teams. He said 33 fire department employees responded to the scene.

"We've had several instances out here where we've had lightning strikes," Gross said.

In June 1995, lightning injured three people, one critically, as they huddled under a tree before an RFK concert by Bob Dylan and the Grateful Dead.

"It sounded just like an explosion . . . loud enough to shake you off your seat," said Gene Perez, of Herndon, who saw the lightning strike from 20 feet away. "I couldn't believe it was that close until I saw the guy down. He had no shirt on. They tried to give him CPR for a couple of minutes before they carried him away on the stretcher."

"I saw a bright orange whitish flash and heard a big boom," said Grace Delacruz. "Everyone got up and started looking around. We didn't know if it was lightning or a gunshot."

Medical workers carried those who were hit by lightning to the field, where they were loaded into ambulances and rushed to the hospital.

Before the lightning struck, the field "was so crowded, you couldn't breathe. You couldn't move," said Julie Glur, 25, of Falls Church.

She said a friend, Dana Justice, 28, was lifted by those in the crowd nearest the stage and passed from person to person overhead to a first aid station after she was accidentally burned by a cigarette.

"It was so crowded in there, I couldn't get my feet on the ground," Justice said. "Everyone was so close that I was up in the air."

John Masoudpour, 19, of Potomac, said security guards moved through the crowd as the rain started, telling people to go inside. He said they issued this warning a couple of times, including five to 10 minutes before the lightning struck.

"Nobody really wanted to move, 'cause they thought it was like a passing shower," Masoudpour said. Hancock "was playing. {Concertgoers} were like, rain or shine. They were like, forget it. Then the lightning struck."

James Wilson, an usher supervisor for the D.C. Sports Commission, said he "got a warning on my radio about an hour and a half or two hours before {the storm started.} Severe thunderstorms, lightning and heavy rain."

Wilson said he didn't do anything about the warning because a decision about whether to stop the concert or warn the crowd was up to the event organizers.

Gross said the fire department doesn't "assume responsibility until after the emergency occurs, and then we would assume command."

The concert was planned and promoted by the Milarepa Fund, a nonprofit group from San Francisco at the forefront of a growing political movement to free Tibet. Adam Yauch, a member of the Beastie Boys, a popular rock band, helped organize the event after meeting Tibetan refugees during treks through Nepal.

Yauch, Sean Lennon and other rock stars have been promoting this weekend's concert and a mass rally planned for Tibet tomorrow at the U.S. Capitol to ratchet up pressure on President Clinton before his official visit to China this month.

Tibetan exiles and other activists working to free Tibet from Chinese occupation want Clinton to raise the issue of Tibet with Chinese leaders and demand that they meet with the exiled Dalai Lama or his representatives to negotiate freedom for Tibet.

Clinton "needs to go in there and ask for negotiations with the Chinese government and the Tibetan government {in exile}," Yauch said at a news conference yesterday morning before the concert started. "If he comes back having achieved anything less than that, his visit will have been a failure."

After their good intentions had been thwarted by a bolt of lightning and a savage storm, concert fans were left in a daze, some angry, some confused.

"It said rain or shine on the tickets," Eric Yandrofski, 17, of Frederick, Md., said after the show was canceled. "It's a shame, but they shouldn't have canceled {the rest of the show}, because no one else is going to get struck by lightning."

Yandrofski's friend Scott Humphreys, 21, of Greenville, S.C., was more philosophical. "I'm disappointed, and I hope {the victims are} okay. But the whole reason they are having the concert is to raise money for the Milarepa Fund, and at least they have the money."

After leaving the concert, the crowd quickly overwhelmed the nearby Stadium-Armory Metro station. The throng spilled onto 19th Street SE, blocking Metrobuses. Some concertgoers walked to Potomac Avenue Metro, the next closest station.

Sam Jordan, chief of the D.C. Office of Emergency Preparedness, called the tragedy a "catastrophic event." But he said the crowd was well behaved, in part because there was no alcohol allowed inside the stadium.

"Cool heads prevailed," Jordan said. Staff writers Patricia Davis, Peter S. Goodman, Richard Harrington, Michael D. Shear and Alona Wartofsky and special correspondent Mark Jenkins contributed to this report. CAPTION: Paramedics place an injured concertgoer in an ambulance at RFK Stadium, where lightning struck as 66,000 were attending the Tibetan Freedom Concert. CAPTION: Ambulances had to force their way through a packed field of people to reach those hurt by lightning during the Tibetan Freedom Concert. There were 66,000 tickets sold for yesterday's concert. CAPTION: Members of the sellout crowd overwhelm a security guard as they rush the field during the summer's biggest rock event. CAPTION: Staff members clear the field after fans descended and bottles flew.