It was no accident that of the weak-end's four dance-events, three took place out of doors: Warm weather primes dancers for this kind of busting loose. But so does Washington itself, a city of notable open spaces, great natural theaters of monuments and parks, and a ready-made, footloose audience. In recently years, Washington's resident dance artist have seized upon these advantages of site and circumstance, and turned them to splendid creative advantage.

The most formal of the open-ait events was the Erick Hawkins Dance Company appeareance at Wolf Trap Saturday night, which was in essence, an indoor concert in a theater with no walls. The company, looking better in every way than its recent Lisner engagement, seemed much enchanced by the Wolf Trap setting and drew upwards of 2,000 enthusiatic people, despite rain, smog and gnats.

The air and surrounding greenery also made a fiting backdrop for Hawkins' choreography, which is in touch with nature in many different senses. This was evident in the evening's one area premier, a 1975 opus called "Death Is the Hunter," with superb props and masks by Ralph Lee, striking constumes by Willa Kim, and an aptly keening astringent score (Wallingford Riegeer's "Study in Sonorities").

The work has the form of a primitive ritual, envisaging the masked figured of death (Erick Hawkins) as a relentless hunter who stalks his mortal prey in the unhurried certainty of triumph. On one side of the stage is a stylised clump of forest, Death's hiding place; on the other, a "cemetary" of stylised headstones. The masked dancers enter and gyrate like a flock of birds, sometimes apart from each other but always bound together by an invisible thread of destiny. Death marks each out in turn with it bow and arrow, and singly, they remove their masks, crumple and fall.

The mysterious ceremony is strangely moving, but the aura is not so much tragic as fateful. Hawkins shows us death as the inevitable completion of nature's endless cysle. The removal of the masks in the moment of dying suggests a release from the bondage of life's pretensions, and the mood of the dance, though dark, is also tranquil. It is an Eastern view of mortality, consonant with Hawkins' larger esthetic outlook.

Yesterday afternoon, the Dance Construction Company commandeered the monument area of Theodore Roosevelt Island for a blithe, multi-layered dance event called "Sunday Maneuvers," featureing three soloists cavorting sculpturally on stits or in fountains, and independent ensemble in gym togs executing drills around them. Meanwhile, in the surrounding shallow pools, a separate wading contigent enacted "Moat Boat," a kind of baptismal idyll featuring woodwind players in rubber floats. Less specifically related to its site, but with a similar sense of spontaneous exuberance, was james Cunningham's "One More for the Road" taking its cue from highway activity of various sorts.

The indoor event was "Summerdance," an anthology of local and invited performances at St. Mark's Church sponsored by the St. Mark's Danced Company. By far the most distinguished entry was Carol Fonda's "I, Flamingo," engagingly performed by Beth Burieson.