The game was suspended with 33 seconds left in the first quarter.
The Cowboys and Broncos are scheduled to resume their game shortly.
The teams returned to the field at 5:45 p.m. EST for a 15-minute warm-up and the game is supposed to resume at 6 p.m. EST, according to Cowboys executive Derek Eagleton.
The teams were sent back to their locker rooms with 33 seconds remaining in the first quarter after their game was suspended by officials due to severe lightning activity in the area.
Patrick Smyth, a Broncos executive, said the delay could last around an hour.
The Broncos held a 7-0 advantage thanks to a Trevor Siemian touchdown pass to Emmanuel Sanders.
When the game resumes, Dallas will have the ball facing second-and-10 at the Denver 46.