Three firefighters were injured after two giant store signs came crashing down at the scene of a fire in Washington Heights. Flames broke out at 1281 St Nicholas Ave. near 174th Street just before 2:30 p.m. Saturday. The firefighters had just finished putting out a fire that swept through the stores - a snack shop and a beauty salon. Dozens of EMS rushed to help the firefighters, who were brought to the hospital and treated for minor injuries. The cause of the fire remains under investigation.