How MassOutage calculates every number

Live outage counts

The national base is ODIN (DOE/Oak Ridge National Laboratory), which collects near-real-time reports from participating utilities. On top of it we add statewide emergency-management aggregators (e.g. MEMA, Cal OES) and major utilities’ public outage maps. Where one source authoritatively aggregates a whole state, other sources’ rows for that state are dropped so a customer is never double-counted. Where a feed reports only a utility- or state-wide total, that total counts toward the state figure but is never assigned to a specific county — it is shown as unmapped rather than guessed.

Average hours without power per customer

History comes from EAGLE-I (DOE/ORNL), which recorded county-level outages at 15-minute resolution from 2014-11 onward. We fold those readings into outage eventsand sum customer-minutes without power over a year, then divide by the customers tracked in that county — giving an annual “average hours without power per customer” figure analogous to the utility reliability metric SAIDI. Because EAGLE-I coverage varies by year, each county page shows the share of customers tracked so the figure can be read in context.

Estimated restoration time

Shown only during a genuinely meaningful active outage (moderate severity or worse). It is the median duration of past outages of a similar size in that same county, drawn from the EAGLE-I event history, with the sample size stated on the page. “Taking longer than usual” is judged by how long the current outage has actually been running versus that historical median — not a static size comparison. This is a historical estimate, not a utility’s official ETA, and it is labeled as such wherever it appears.

Utility reliability — SAIDI, SAIFI, CAIDI

Reliability metrics and service territory come from the US EIA Form 861. SAIDI is the average duration of interruptions per customer per year; SAIFI is the average number of interruptions; CAIDI (SAIDI ÷ SAIFI) is the average length of a single interruption. We report the IEEE-standard figures, which include major event days. Provider rankings order utilities by SAIDI (lower is more reliable) among those of comparable territory size.

County electricity price estimate

Retail electricity prices are not published at the county level. We derive a county estimate by taking each serving utility’s residential price from EIA-861 and combining them, weighted by each utility’s residential customer count where that count is available (a simple average otherwise). Because utilities report customers at the state level, a true per-county customer share is not available — this is an estimate, labeled as one on every page it appears.

Hazard & outage risk

Per-hazard ratings (hurricane, tornado, ice storm, wildfire, flooding, and others) and the social-vulnerability rating come from FEMA’s National Risk Index. The composite outage-risk tier shown on each county page combines FEMA’s weather-hazard exposure with that county’s own decade of observed outage hours, so it reflects both what the county is exposed to and what it has actually experienced.

Limitations

• Outage data is only as accurate as utilities report it.
• Live and historical figures use different sources and are never summed together.
• Live coverage is partial; many small cooperatives and municipal utilities publish no clean public feed, so some counties have no live data.
• Very short outages (under ~15 minutes) may not appear in the historical record.
• County price and restoration figures are derived estimates, not official utility numbers.
• MassOutage is not affiliated with any utility or government agency.