What happens if the power grid goes down?

If the power grid goes down, the effects depend on how widespread and how long the outage lasts, but the general pattern is:

• Immediate disruption: Lights, heating/cooling, appliances, and most home internet service stop working. Traffic lights can go out, causing congestion, and elevators may stop.
• Communication problems: Cell service may keep working for a while, but towers and network equipment depend on backup batteries or generators, so service can degrade if the outage lasts.
• Water and sanitation issues: Some water systems and pumps need electricity, so water pressure can drop and treatment systems may be affected if backup power is unavailable or fuel runs out.
• Food and commerce impacts: Stores, ATMs, card readers, gas pumps, and other payment systems may stop working. Refrigerated and frozen food can become unsafe if the outage lasts long enough.
• Healthcare and emergency response: Hospitals usually have backup generators, but prolonged outages can strain fuel supplies and operations.
• Longer outages: If transmission equipment or transformers are damaged, restoration can take much longer, and supply chains, wastewater systems, and emergency services may all be affected.

A practical rule of thumb is to be prepared for at least 72 hours without power with water, nonperishable food, flashlights, batteries, medicines, and some cash. Exact outage effects and timelines can vary, so if you need up-to-date guidance for your area, check your utility or local emergency management source.