According to CDOT, a stretch of I-25 near Thornton will be closed, starting tonight (October 4) and will continue tomorrow as well. 

XtremerX/ThinkStock

 

Due to construction work, southbound I-25 will close completely between 136th Ave. and 120th Ave. from 10 p.m. - 5:30 a.m. on Wednesday, October 4 and again on Thursday, October 5. CDOT says a detour will cause a 25 minute delay for commuters at that time.

More about this construction project can be found here.