Not long after the traffic thinned from last night's Capitals game against the New Jersey Devils, Capital Centre bustled with activity in the early morning hours.

The ice was melted, the plexiglass and sideboards were dismantled and about 50 truckloads of dirt were hauled into the arena. The preparations, which will continue today, are for the expected onslaught of hundreds of horses arriving this morning for the 32nd annual Washington International Horse Show.

More than 800 entries are expected to compete through next Sunday, including equestrian teams from the United States, Canada, France and Great Britain. The international horse-and-rider pairs, four for each team, will compete nightly in an open jumper event. U.S. Equestrian Team members are Alice Debany, Tony Font, Hap Hansen and David Raposa.

Hansen, 37, of Encinitas, Calif., currently the top rider on the American Grandprix Association circuit with six victories this year, leads the team. Debany, 22, from North Salem, N.Y., won the junior jumper championship here in 1986. She has won two grandprix titles this year.

Font, 31, a Silver Spring native living in Houston, won the prestigious AGA Championship last December in Tampa. Raposa, 26, of Clinton, N.Y., is a three-time winner of the USET Show Jumping Talent Derby, a competition to help develop talent in young riders. He represented the U.S. team in the World Cup in Germany last year.

A U.S. team is selected for each major horse show based on combined prize money won by horse and rider this year.

Hunt Night is the feature event tonight with local teams competing over courses simulated to test hunt skills. Also tonight, amateur-owner jumpers will compete in a power and speed class, a preview to Monday's jumper classic, the Ambassador's Cup.

International Open Jumper classes begin Tuesday. The Costume Pair Relay, in which teams of two compete in the open jumper class, is Wednesday. Ladies' sidesaddle is Tuesday and Wednesday.

The U.S. team will attempt to match last year's faultless performance and defend its title in the Nations' Cup Thursday night.

One of the show's most popular events, the Puissance, or high jump, is Saturday night. Riders will attempt to break the indoor Puissance record of 7 feet 7 1/2 inches set in 1983 by Anthony D'Ambrosio and Sweet N Low. The local pony finals, featuring young area competitors, start Saturday at 2 p.m.

The highlight next Sunday is the show's premier event, the $40,000 President's Cup, a grandprix event featuring some of the top riders in the world.