Firefighters are working on a blaze north of Rifle that grew rapidly yesterday. The fire was reported around 1:00PM yesterday afternoon, and when firefighters arrived it was only a few acres. Due to strong winds associated with a cold front, the fire blew up to 500 acres as of this morning. Crews had to shut down a portion of highway 13 for a few hours yesterday, that road has since reopened. The cause of the fire is under investigation but it may be human caused. More than one hundred firefighters and two aircraft are expected to be fighting the fire today and no evacuations have yet been ordered.