It won’t actually be close to that high I expect...Texas City and Halifax were a LOT bigger, but only about 3 kilotons.
Effects radii for 1 kt blast (smallest to largest):
Fireball radius: 0.03 km / 0.02 mi (2,884.84 m² / 31,052.18 ft²) Maximum size of the nuclear fireball; relevance to lived effects depends on height of detonation.
Air blast radius: 0.28 km / 0.17 mi (0.25 km² / 0.1 mi²) 20 psi overpressure; heavily built concrete buildings are severely damaged or demolished; fatalities approach 100%.
Thermal radiation radius: 0.69 km / 0.43 mi (1.48 km² / 0.57 mi²) Third-degree burns to all exposed skin; starts fires in flammable materials, contributes to firestorm if large enough.
Air blast radius: 0.74 km / 0.46 mi (1.72 km² / 0.66 mi²) 4.6 psi overpressure; most buildings collapse; injuries universal, fatalities widespread.