An onstage rainstorm suddenly brought the second day of tech rehearsals for Singin' in the Rain to a halt. The spectacle inside Seattle's 5th Avenue Theatre brought performers, stagehands and technicians to their feet, and cheers broke out when actor Micahel Gruber began dancing and tapping through the drenching rain, splashing in the puddles and, of course, singing.

"I don't know why that makes me feel happy every time I see it, but it does," says dancer/singer Maya Perkins, who performed in a recent production of the show in Houston.

"That's the first time we've run the rain scene," says Andy Luft, the 5th Avenue's productions supervisor, who's been closely involved in the planning and peparation for the rain effects. "It looks good."

Ten days earlier, the various components of this downpour filled the narrow alley behind the downtown Seattle theater with what looked like the spilled contents of a giant puzzle box. It was up to Luft and his colleague, shop engineer and draughtsman Charlie Bulli, to make them into a real onstage rainstorm. The hole-filled pipes needed to produce it were tucked into a long wooden box, waiting to be washed clean of debris before being hung almost 80 feet above the stage. Two 250-pound tanks of water, each with its own pump, were concealed in 6-foot crates.

Bulli checked off the various components on his clipboard as Luft looked after 48 workers, including 14 house crew and 34 additional hands, for the load in. Both men were calm and cheerful in the midst of the hullabaloo and took a few minutes to explain the process behind the precipitation.

The 250-pound water tanks would stay in the alley throughout the run, due to their weight and the space limitations backstage. The water in the tanks, heated to between 120 and 130 degrees, would be linked by flexible piping (similar to fire hoses) to a valve set that sends water via three pumps to the stage. Two of the pumps would send water to the two hanging perforated pipes, one placed so that the rain falls on the upstage elements of the rain deck's scenery. The third pump would send water to a gutter set up to spit rain into Gruber's face during the performance. A fourth pump, located inside the tank within the rain deck, would send water back out once it had fallen onto the stage, and would run through a drain designed to look like a regular street drain covered with an iron grill.

Luft and Bulli had to choose two of three pipes with varying sizes and perforation shapes that can alter the look and feel of the rain. They chose smaller meshed holes for a finer, mistier downpour.

The rain deck, which is able to receive and return water, was a crucial element of the whole effect. The heavy deck, built on a series of 4-inch casters, was pushed forward on the stage before the scene, an operation that took eight stagehands. Both the deck and the scenery were angled and crowned so that the falling rain and the water running down from the gutters would go into the street drain. From there, a scupper system inside the deck would send water into the interior tank to be pumped back outside to the large tanks. (Scupper is a nautical term describing the indentations that conduct the water from the bilge.) The effect was wired so that if the rain deck was not in place under the rain pipes, the water would not flow. A safety sensor would turn the water off if the electricity to the fourth pump went out. (If this happened, there would be no way for the increasing store of water to be removed from the deck.)

A puddle-sized indentation in the platform pooled the water so the actor could, stamp his feet and splash water around. The surface of the deck was coated with sand to help prevent slippage.

Gruber had three microphone transmitters available to him during the rain scene. He changed to a new one automatically after the scene, in case any water seeped through, and had the third standing by just as a precaution.

Fortunately, the rain scene came before the intermission, allowing time for the inevitable mopping-up operations. "Despite all the precautions, it's easy in all the splashing and dancing for some five or 10 gallons of water to get on the stage," says Bulli. Luft was relieved that he didn't have to worry about water spoiling the theater stage. The old Masonite floor, covered with hundreds of coats of paint, is impervious.

The distribution of water was especially tricky in terms of space in the tight quarters of the theater. Each of the set pieces, including a sofa, fireplace and curved Busby Berkeley platform, were hung on hooks and hauled up by a half-ton motor into the flies as soon as they were taken offstage after each use. "Work has been going on planning for the storage of this show since June," says Luft. "Every footprint of space is specified."

Luft was quick to point out that, as tight as the theater may have seemed for such a big-scale production, the 5th Avenue is the same size as 90 percent of Broadway theaters, making it an excellent tryout venue. "If you can fit it in here, you can fit it on Broadway," he says.

After the rainstorm, rehearsal returned to its regular rhythm. The actors and stagehands resumed their places. The stage was mopped up, adjustments made, and it was time to run the scene again. Gruber put on his rain slicker. Rain had come again to Seattle, and the wonderful sound of splashing echoed both inside and outside the theater.