It looks like it could be cheat grass, though grass identification can be tricky.  For a positive identification it might be best to bring in a sample.  For residents of Boulder County the first 2 plant ids are free.  We would need a full plant with roots and blades, but assuming we are correct from the pictures…

Cheat grass (also known as downy brome) is an annual and is problematic as it dries up in summer, providing fuel for grass fires.  There are some means of dealing with this that include tilling, grazing and chemical solutions (ex. RoundUp).  Mowing is generally not recommended since it does not kill the plant and it can still go to seed.

We are including a link to a PDF that provides more detailed information on the above, including information on identification that may help.  On the second page is further information on eradication. 

http://extension.colostate.edu/docs/pubs/natres/06310.pdf

Additionally here is a link to a newsletter that has an article on cheat grass, but more importantly it has pictures for identification (page 3).

http://www.ext.colostate.edu/sam/nl/14-winter.pdf

If you have any further questions, please let us know.