A cloudburst is a weather phenomenon characterized by sudden and intense rainfall over a small area. Option 1 accurately defines a cloudburst as a short-lived period of heavy rain that can last for only a few minutes. This means that a cloudburst is a localized event, typically affecting a small geographical region.

Option 2 states that a cloudburst refers to 50 mm of rain over a period of time. This definition is not accurate because a cloudburst is not defined by the amount of rainfall, but rather by its intensity and the suddenness with which it occurs.

Option 3 suggests that a cloudburst is caused by the rapid condensation of very high clouds. While it is true that condensation is involved in the formation of rain, this option is not specific to cloudbursts as other types of rainfall also involve condensation.

Option 4 states that a cloudburst refers to a thunderstorm with little rain. This definition is incorrect as a cloudburst is characterized by heavy rainfall, not by the presence of thunder or lack of rain.

In conclusion, option 1 is the correct definition of a cloudburst, and the other options are either inaccurate