Act of God is a legal term for events outside of human control, such as sudden floods or other natural disasters, for which no one can be held responsible. This does not protect those who put others in danger of acts of God through recklessness, such as a camp counselor who instructs a group of children on a hike to stand under a tree to escape a lightning storm.

A better example is that of pluviculturalist Charles Hatfield who was hired by the city of San Diego to fill the Morena reservoir to capacity with rainwater for $10,000. The region was soon flooded by heavy rains, bursting the reservoir's dam, killing nearly 20 people, destroying 110 bridges (leaving 2), knocking out telephone and telegraph lines, and causing an estimated $3,500,000 in damage in total. When the city refused to pay him (he had forgotten to sign the contract), he sued the city. The floods were ruled an act of God, excluding him from liability but also from payment.