The headline figure is the percentage of tracked customers out: the number of accounts without power divided by the accounts a utility serves in that area. A “customer” is a metered account — one household or one business — not a person. Because a household can be several people, the number of people affected is always higher than the customer count, often by two or three times.
Percentages and raw counts tell different stories, so read both. A rural county might show 40% out from only a few hundred customers, while a dense city at 4% out can mean tens of thousands of people in the dark. The percentage tells you how saturated an area is; the count tells you how many are affected.
Most utilities publish an estimated restoration time, or ETR — their best guess for when power returns. An ETR is an estimate, not a promise. Early in a big storm a utility may not post one at all until crews have assessed the damage, and a posted time can slip as they find more breaks than expected.
Finally, the map is only as fresh as its feed. Each utility refreshes on its own schedule and some report more completely than others, so a quiet area on the map can mean the lights are on — or that a particular utility simply has not reported yet. Treat the data as a strong, current snapshot rather than a perfect census.