Like so many of the heroines she has portrayed, Birgit Nilsson is an elemental force. Only a phenomenon could look and sound as splendid as this 61-year-old soprano did last night in her Kennedy Center appearance at a benefit for the Washington Opera.

Just as a person caught in a hurricane is not inclined to stop and clock the winds, one did not want to spend time monitoring Nilsson's control over pitch and tone. So much of this immense talent was still intact and the right moments were so powerful that one simply surrendered to this extraordinary presence.

After a splendidly paced performance of Wagner's overture to "Rienzi" by Rudel and the Opera House orchestra, Nilsson came on stage in a flowing purple chiffon gown. The audience stood to welcome her with cheers and applause. The expressiveness in her voice when she began "Dich, teure Halle" from "Tannhauser" sent a rush of excitement -- and relief -- through the house. This was the Nilsson one had hoped to hear.

Gaining in strength as she sang a moving "Liebestod" from "tristan und Isolde" and an effective "Pace, pace" from La Forza del Destino," Nilsson reached her finest peak in the closing scene from 'Salome." When she finished, the audience stood on its feet and roared and clapped for five minutes until Nilsson obliged with the evening's most expansive moment Brunnhilde's rousing "Ho-jo-to-ho!" from "Die Walkure."

The audience still would not let her go. Rudel had kissed her. She had kissed Rudel and given him and the two first-chair violinists each a rose. She expressed doubts about her voice by pointing to her throat. The cheering turned to rhythmical clappling. Finally Nilsson, with once again the most sympathetic accompaniment from Rudel and the orchestra, closed with "Vissi d'arte" from "Tosca."