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Rolling blackouts: What they are and why they happen

Snow covered city streets including at 61st and Sheridan in Tulsa as a winter storm moves in to northeast Oklahoma on Sunday, Feb. 14, 2021. (John Clanton/Tulsa World via AP)

(NEXSTAR) – As extreme cold and snowstorms slam of the U.S. Monday, some cities are experiencing widespread rolling blackouts.

But what is a rolling blackout and why is it necessary?

According to Direct Energy, an energy provider in the U.S. and Canada, rolling blackouts are “systemic, temporary power outages that help bring balance to the supply demand of electricity in the market.”

Generally, rolling blackouts occur as the “last step in a series of emergency procedures” when a power supply shortage is detected in a market. They help to prevent widespread blackouts across a region.

Rolling blackouts generally occur in one area at a time and last for a few hours, but the length of the blackout depends on the severity of the event.

Utility providers decide which parts of the city will be subject to rolling blackouts and try to avoid areas with hospitals, medical centers or downtown regions, for which electricity is vital.

Reliant Energy, a Texas utility provider, offered the following tips to Nexstar affiliate KIAH to help Houston-area residents prevent rolling blackouts: