The biggest snowstorm to hit DC, certainly in the 20th century, occurred on January 27th and 28th of 1922. The accumulation caused the roof of the Knickerbocker Theater to collapse; 96 were killed by the collapse. Real oldtimers know what was showing at the time.
Historic NWS Images
The Knickerbocker Snowstorm January 27-28, 1922