University College London is apologizing for a tweet that it says was a reference to the possibility of snow on campus, but that has been widely criticized as racist. Here's the tweet.

Dreaming of a white campus? Our campuses will be open and operating fully today, Monday 11 December, so please make your way in as planned. (We can't guarantee snow but we'll try!) #snowday #londonsnow — UCL (@ucl) December 11, 2017

With many denouncing the tweet, the university apologized and said it had been trying to reference a famous Christmas song.