Answer Description

Brownouts, or temporary power drops in voltage, are as dangerous to systems as blackouts. Any interruption of voltage to a computer can cause damage or loss of data.

Wikipedia

A brownout is an intentional or unintentional drop in voltage in an electrical power supply system. Intentional brownouts are used for load reduction in an emergency. The term brownout comes from the dimming of incandescent lighting when the voltage reduces. A voltage reduction may be an effect of disruption of an electrical grid, or may occasionally be imposed in an effort to reduce load and prevent a power outage, known as a blackout. Brownouts can also stem from an excessive demand in electricity or when severe weather events occur.In some countries, the term brownout refers not to a drop in voltage but to an intentional or unintentional power outage (or blackout).