PLYMOUTH MEETING, Pa. (CBS) — A woman is dead and dozens of others were displaced after a fire ripped through an apartment complex in Plymouth Meeting, Montgomery County.

Flames broke out around 10:30 p.m. Saturday in Building D of the Plymouth Rock Apartments along the 1900 block of Sandy Hill Road and quickly escalated to three alarms.

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Within an hour, heavy flames tore through more than a dozen apartments and caused heavy damage to the roof and other areas of the building.

Fire officials say the building’s sprinkler system was not working properly and there was a damaged hydrant which caused some challenges in controlling the fire, but fortunately most of the residents heard the smoke alarms and were able to get out safely.

Thirty residents were evacuated from their apartments and firefighters had to rescue one woman from her balcony.

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Sadly, one person was unable to escape the fire. Firefighters discovered the body of a woman inside a burned apartment.

Nineteen apartments were damaged in the fire.

The American Red Cross was assisting the families who were displaced by the blaze.

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Fire officials and the Montgomery County District Attorney’s Office are investigating the cause of the fire.