The Denver area was pelted with an intense bout of hail amid severe thunderstorms Monday afternoon, halting area traffic and putting the airport on a ground delay.

After the morning was dominated by sunny skies, dark clouds rolled in just after noon, giving way to heavy rain around 1 p.m. That rain then turned to hail, about a quarter inch in diameter, that descended upon the downtown area, driving pedestrians to find cover under building overhangs.

The intense weather also put Denver International Airport into a ground stop until 2:30 p.m. Monday, according to the Federal Aviation Administration. As of 2 p.m., 333 flights have been delayed and four have been canceled, according to flightaware.com.

The Denver area will remain under a severe thunderstorm watch until 8 p.m. Monday, with temperatures staying in the high 70 degrees, according to the National Weather Service. Additional showers and storms could roll in between 11 p.m. and midnight Monday, as well as after 3 p.m. Tuesday.