Updated 02/02/11 – 6:30 p.m.

CHICAGO (CBS) — Chicago Public Schools will be closed for a second day on Thursday in the wake of a blizzard that dumped 20 inches of snow on the city. The City Colleges of Chicago and all Catholic schools in Chicago also will be closed.

“Because of the severity of this blizzard, it is very clear that many of our personnel, teachers and especially our students are simply physically unable to get to our schools,” CPS Chief Executive Officer Terry Mazany said Wednesday afternoon. “Because of that, we have determined that we will, for the second day, close our schools. We will not have school on Thursday.”

It is the first time since 1999 that Chicago Public Schools have been closed for snow.

The city is concerned about getting enough buses on the streets as well as getting the streets, sidewalks and areas around schools cleared of snow.

Mazany also said that 26 public schools were without power on Wednesday and officials were concerned they would not have proper heat in time for school on Thursday.

Officials will decide on Thursday whether or not Chicago Public Schools will reopen on Friday.

The City Colleges of Chicago also will be closed on Thursday and classes are expected to resume on Friday.

The Archdiocese of Chicago’s Office of Catholic Schools said officials have urged its 256 schools across Cook and Lake counties to remain closed for a second day.