GLENDALE, Ariz. -- A fast-moving fire forced a man and his grandson out of a Glendale home Saturday afternoon.Glendale firefighter Daniel Valenzuela said the man called 911 around 1 p.m. after seeing a fire in the back patio area of his home near 57th and Northern avenues.The house was fully engulfed in flames when firefighters arrived a few minutes later, Valenzuela said.More firefighters were called to help battle the blaze in the triple-digit heat. Valenzuela said the Phoenix and Peoria fire departments also responded."Fighting fire is a daunting task, a physical task as it is," he said. "Then you do it in this heat and it becomes even more difficult."Firefighters were also concerned about propane tanks on the property and downed utility lines around the home.No injuries were reported.The cause is under investigation.