There have been several sightings of a young mountain lion in the area. Remember, if you encounter a mountain lion, do not run. Instead, face the animal, make lots of noise and try to look bigger by waving your arms and throw rocks or objects to scare it away. If attacked, fight back.
The Pasadena Humane Society has posted a Mountain Lion Awareness flier and the City of Glendale has created a wildlife sighting website where you can see and post sightings of different types of wildlife in the city. The site is relatively new so there are not many postings yet. You can read more about this website in this article by the Glendale News Press: http://articles.glendalenewspress.com/2013-06-06/news/tn-gnp-mountain-lion-spotted-in-glendale-neighborhoods-20130606_1_mountain-lion-rossmoyne-wildlife-sightings