Here's some cheery information C&P from one of the nuke map sites, just describing the parameters of the results it gives. These categories are like concentric rings, going from the smallest in the middle outwards:
Fireball radius:
Maximum size of the nuclear fireball; relevance to lived effects depends on height of detonation. If it touches the ground, the amount of radioactive fallout is significantly increased.
Air blast radius (20 psi):
At 20 psi overpressure, heavily built concrete buildings are severely damaged or demolished; fatalities approach 100%.
Air blast radius (5 psi):
At 5 psi overpressure, most residential buildings collapse, injuries are universal, fatalities are widespread.
Radiation radius (500 rem):
500 rem radiation dose; without medical treatment, there can be expected between 50% and 90% mortality from acute effects alone. Dying takes between several hours and several weeks.
Thermal radiation radius (3rd degree burns):
Third degree burns extend throughout the layers of skin, and are often painless because they destroy the pain nerves. They can cause severe scarring or disablement, and can require amputation. 100% probability for 3rd degree burns at this yield is 8.4 cal/cm2.