"The Snow Storm," writes Kim Roberts in her book A Literary Guide to Washington, DC (2018, Univ. of Virginia Press), "was DC's first race riot. It was begun in August 1835 with an alleged nighttime attack by Arthur Bowen, a nineteen-year-old slave, upon his owner, Anna Maria Thornton, aged sixty, widow of the architect of the Capitol, William Thornton."
Bowen was imprisoned. A mob of mostly Irish immigrant laborers tried to storm the jail, located on the site of present-day Judiciary Square, in order to hang him. The Mayor, District Marshal, and U S District Attorney (as U S Attorneys were then called) worked to pacify the mob; when their efforts failed, Marines were sent to guard the jail. The mob then went off and burned or damaged a number of churches, schools, homes, and businesses run by or for blacks-- including a restaurant run by a certain Mr. Snow (thus the "Snow Storm").
Here's a contemporary diarist's account of the events:
"The 7 of August 1835 on friday it was reported that Mrs Doctor Thornton young Mulatto man said that he was going to knock his mistress in the head with axe and he were arrested and put in the Jail still the mob raged with great vigor and as fast as they were arrested they were lodged in Jail on the 8 day of August 1835 on saturday the mob surrounded the Jail and swear they would pull the Jail down and the Constable makin threats they said their objects was to get Mrs Thortons Mullateto man out and to hang him with out Judge or juror and evry effort was made by the Marshal of the District and the united States District Artoneny lawer Frances key Sr and the Hon Wiliam A Bradly that wher Mayo[r] of washington at that time evry efert wher made by the oficers to preserve peace and harmony among these men but all of it appeard in vain and they wher not surfichient Milertary force to guard the Jail..."
The Attorney? Francis Scott Key, author of the words to "The Star-Spangled Banner." The diarist? Michael G. Shiner, a former slave, freed in 1836, who worked at the Navy Yard. Read his memoir-slash-diary, "the earliest known by a DC resident of African descent," according to Ms. Roberts.