San Francisco Example: 9 seconds after detonation
An overpressure of at least 10 psi extends out for 2.7 miles. Most concrete and steel reinforced structures will be destroyed or severely damaged. All non-reinforced structures will be leveled. Some buildings will be shielded by the hilly terrain of the city and suffer reduced damage. However, even these structures will likely have their interiors destroyed. The thermal pulse will be attenuated by the fog to less than 2 calories per square centimeter.
Most people inside buildings will be killed by flying debris or die as the buildings collapse. Those in the direct line of sight will be blinded by the flash but will receive no other injury from the much attenuated thermal pulse. Fatalities are estimated at 120,000 with another 30,000 injured but alive.