With Chile leading 2-0 at half-time at Soldier Field, a heavy storm rolled into the region forcing stadium officials to delay the start of the second half.
Tens of thousands of spectators were ordered to take shelter inside the stadium, leaving the ground empty as torrential rain pounded the stands.
Lightning lit up the stadium backdrop as loud crashes of thunder sent fans scurrying for cover.
The storm created the very real prospect of the match not being completed Wednesday.
Under tournament rules, if play is suspended for more than three hours the match will be called off and resumed on Thursday, kicking off at half-time with Chile leading 2-0.
The dramatic intervention of Mother Nature came after defending champions Chile had put one foot in Sunday’s final with a devastating first half display.
The Chileans had roared into a two-goal lead to leave Colombia reeling inside the first 11 minutes.
Jose Pedro Fuenzalida was the architect of the opening goal, racing clear of the Colombian defense with an electric burst down the right flank before crossing to Alexis Sanchez.
Sanchez was beaten to the ball by Colombia’s Juan Cuadrado, but the Juventus player could only succeed in heading back to the feet of Charles Aranguiz who tapped in from close range to make it 1-0 after seven minutes.
Four minutes later, Chile doubled their lead.
Sanchez turned Santiago Arias inside out on the edge of the penalty area before unleashing a fierce low shot which struck the bottom of the post.
The ball rolled into the path of Fuenzalida who had the simplest of finishes to make it 2-0 after only 11 minutes.
Chile looked sharper across the pitch but inevitably they were unable to maintain their frenzied pressing and Colombia gradually came into the match.
Colombia striker Roger Martinez forced a smart save from Chile goalkeeper Claudio Bravo in the 24th minute and nine minutes later the Barcelona stopper was pressed into action again when Arias advanced into the area and shot.
The winner of the semi-final will face Argentina in Sunday’s final in East Rutherford, New Jersey.