ABC News’ Ann Compton (@AnnCompton) and Mary Bruce (@MaryKBruce) report:

The usually unflappable White House was thrown into chaos this morning moments before the South Korean president was to arrive for the formal welcoming ceremonies. Last-minute rain forced the huge military extravaganza indoors, but the weather lifted moments later and officials decided to move everything back outside.

It was a chaotic scramble as groundskeepers rolled the red carpet back out across the lawn, maintenance men used a vacuum on the carpet and squeegees on the slick driveway where guests wandered in bewilderment, dodging workers with wheelbarrows replacing plants around the stage and soldiers rushing flags back into position. A White House usher used a large white towel to wipe the rain off the presidential lectern and the black binder holding the president’s welcoming speech.

The sound system echoed as a military announcer boomed “Audio check, 1-2-3-4-5? and the elegant chief of protocol, Ambassador Capricia Marshall, phone to her ear, raced inside and a janitor with a broom pushed out the same door past Marines in dress uniform still practicing the ritual technique of opening the door with a smart military maneuver.

Finally, 16 minutes late, the doors opened wide and President Obama and the first lady stepped out, and the rain started to pour again.