Hundreds of students evacuated the Commons dining hall Friday due to a fire alarm that went off at about 12:50 p.m.

Firefighters and Yale Police who arrived on the scene said no fire was found, but that they could not identify why the alarm had been set off. One official said the humidity might have played a role.

Maureen O’Donnell, general manager of Commons, declined to comment.

A Commons employee estimated that about 900 students were in the dining hall when the alarm went off. Skylar Brooks ’11 said it sounded just as she had reached the front of the long line to the Commons servery. The students around her proceeded to pile food onto their trays before exiting the dining hall, she said, though some gave up and left.

“Yalies thinking they can escape anything, including fires,” Jackie Bruleigh ’11 said.

Trays in tow, most students instead ate lunch on and around Beinecke Plaza, where Yale Dining’s Uncommon Market was set up.

“It’s fine,” said Jenna Poggi ’13. “It’s a nice day.”

The dining hall reopened at 1 p.m. Yale Police officers and firefighters on the scene helped themselves to lunch.

A fire alarm also forced students to evacuate the Berkeley College dining hall at about 6 p.m. Thursday.