Between December 24, 1849 – June 22, 1851 six devastating fires ripped through a newly formed San Francisco. Most structures at this time were made of canvas, oilcloth or wood and were easily combustible. There was no organized fire department, and although cisterns were built along the waterfront they were dependent upon the tide and often empty when the tide was low.

The Six Great Fires were as follows:
1) December 24, 1849: At 6:00AM a fire was intentionally set at Dennison’s Exchange, a gambling hall on Washington between Clay and Sacramento. Spectators refused to lend a hand unless they were paid. The fire spread quickly up and down Washington, destroying 290 structures. New structures replaced the ones within a month and the City created a volunteer fire department and supplied them with hooks, ladders, axes and rope.
2) May 4, 1850: At 4:00AM a fire was intentionally set near Portsmouth Square and 16 blocks (300 buildings) burned. Again, bystanders refused to help unless they were paid. When the fire was finally contained, an ordinance was passed that anyone who refused to assist in extinguishing flames or assisting in removing goods would be fined. Additionally, every household was ordered to keep 6 buckets of water at hand and all cloth structures were banned.
3) June 14, 1850: At 8:00AM a chimney fire in a bakery created a firestorm that lasted three days. Everything between Clay, California and Kearny was destroyed. After this fire, wood structures were replaced with fireproof brick buildings.
4) September 17, 1850: At 4:00AM a fire was intentionally set north of Portsmouth Square and 4 City blocks between Dupont (Grant), Montgomery, Washington and Pacific burned. As this district had been burned down in the previous fire, only one-story brick buildings existed and there was very little damage.
5) May 3, 1851: At 11:00PM a fire was intentionally set at a paint and upholstery store above a hotel in Portsmouth Square. High winds and planked wooden streets fueled the blaze. The fire lasted 18 hours and destroyed 18 blocks (three quarters of the City) and somewhere between 1,500 – 2,000 structures. Only five brick buildings along Montgomery survived.
6) June 22, 1851: At 11:00AM a fire was intentionally set on Powell. 16 blocks burned, including City Hall and the Jenny Lind Theater. After this fire, major changes were made to building codes, and all new structures were built with 2-3 foot solid brick walls. Additionally the City built 16 underground cisterns to store water. The first was a 12,000 gallon cistern in Portsmouth Square. A fire department was formed, a Fire Chief hired, and the City bought horse-drawn fire engines. Eventually, 23 cisterns were established between Telegraph Hill and Rincon Hill.

By the end of the century it was believed that the City’s water system of mains and pipes was adequate and the cisterns stopped being maintained. When the 1906 Earthquake^[1] happened the water mains broke, leaving the City completely vulnerable to the ensuing fires that burned down the majority of the City. Some of the old cisterns were able to save portions of the City and afterwards, the City passed a bond that allowed for the building of the Auxiliary Water Supply System (AWSS). In 1908 new cisterns were constructed and older ones were repaired. That system of cisterns still exists: most cisterns hold 75,000 gallons of water while the one below the Civic Center holds 243,000 gallons. These cisterns are easily identified: look for a brick circle in the center of major intersections.

Many believe that San Francisco’s City Flag design was inspired by the 1906 Earthquake and Fires; but actually, the first city flag was adopted in 1900 to commemorate the City’s Six Great Fires, copied from the first official City Seal depicting a phoenix. Out of the over 100 designs submitted, artist John Gamble’s design was selected: a black phoenix rising from gold ashes with the words “Oro en Paz y Fierro en Guerra” (Gold in Peace and Iron in War). In 1940 a new flag was adopted: it depicts a small brown and black phoenix with the same motto and “San Francisco” printed across the bottom. In 2020 local resident Brian Stokle unveiled a new flag: the original phoenix design in red sitting over orange flames with a grey and yellow background and no lettering. A surprising number of residents fly this flag, though all government buildings still use the official 1940 design.