Outages

An outage is a period during which a service or system is unavailable or functioning well below normal levels. Outages can affect utilities such as electricity, water, and gas, as well as information and communications technology, transportation, and other critical infrastructure. Some outages are planned, while others are unplanned.

Common types include power outages (blackouts and brownouts), telecommunications or internet outages, and service outages in software or cloud environments. Outages may affect a single site, a regional area, or large populations, depending on the scale of the failure and network design.

Causes range from severe weather, equipment failure, and physical damage to maintenance work, cyber attacks, overloading, aging infrastructure, and human error. Complex interdependencies mean a fault in one system can propagate across adjacent services, amplifying disruption.

Detection and reporting rely on monitoring systems, customer reports, and incident dashboards. Utilities and operators classify outages by duration and severities (for example, how many customers are affected and how long restoration is expected). Public agencies often provide status updates through official channels.

Response focuses on rapid containment and restoration, prioritizing critical services such as hospitals and emergency communications. Restoring power may involve switching networks, deploying backup generators, or repairing components. Communicating timelines and safety guidance is a common component of incident management.

Mitigation emphasizes resilience, including redundancy, diversification of supply, and robust maintenance programs. Practices such as smart grids, failover architectures, and disaster recovery planning aim to reduce both the frequency and duration of outages and to accelerate recovery when they occur. Metrics such as SAIDI (system average interruption duration index) and SAIFI (system average interruption frequency index) are used to measure reliability.