A nuclear weapon detonation causes an intense blast, intense light and heat, and direct radiation. The blast causes a damaging wave of air pressure. Detonation at or near ground level creates a large airborne cloud of radioactive particles that can contaminate the air, water, and ground surfaces for miles around as radioactive fallout. The heavier particles fall first, nearer the site of the explosion. A very high altitude burst can create an electromagnetic pulse (EMP) that can disable electrical and electronic equipment and systems of all kinds. A nuclear device can range from a weapon carried by an intercontinental ballistic missile launched by a hostile nation, to a small portable nuclear device transported by an individual or terrorist organization. All nuclear devices cause deadly effects when exploded, including blinding light, intense heat (thermal radiation), initial nuclear radiation, blast, fires started by the heat pulse, and secondary fires caused by damage to electrical and natural gas lines, stoves and furnaces, and fallout radiation.