Tournament officials announced that play would resume at 12:10pm local time after the opening round of the US Open Championship was delayed for more than three and a half hours.
With less than two hours' play completed the horn reverberated around Merion to suspend play as a large storm drew near.
Play was suspended at 8.36am with Ian Poulter at the top of the leaderboard after opening with three straight birdies after starting at the 11th but with severe weather moving into the area, officials decided to get everyone off the course.
Nicolas Colsaerts was in the first group off the 11th and picked up two early birdies to lie two under par after seven holes alongside Charl Schwartzel, who similarly birdied the 13th and 14th holes, with another South African Tim Clark and American Charlie Hoffman on the same mark.
The course has already been softened by six inches of rain in the past week.
The delay meant the start time for Tiger Woods, Rory McIlroy and Adam Scott was pushed back to shortly before 5pm, assuming further bad weather had not arrived before then.
