SPA-FRANCORCHAMPS, Belgium—The start of the Belgian Grand Prix was suspended after hours of heavy rainfall made it too risky to begin on time Sunday. A red flag came out shortly after 3:30 p.m. local time following a formation lap and no new start time was immediately given. The 7-kilometer (4.3-mile) Spa-Francorchamps circuit was totally drenched for the scheduled 3 p.m. start, which was twice pushed back to 3:25 p.m. Soaked fans huddled under large umbrellas on muddy banks as they waited for the worst of the rain to pass. The thick clouds and mist hanging over the Ardennes forest also gave the circuit a daunting look and made for poor visibility. When the drivers embarked on their formation laps, several complained. “I really can’t see anything,” said Mercedes driver Lewis Hamilton. The decision to suspend the start was made a few moments later. “It’s wet, but I think it’s fine …