What We Know About the Power Outages in Spain and Portugal

Widespread power outages upended life for millions across Spain and Portugal (and, briefly, parts of France) on Monday.

Traffic lights went dark at busy intersections. Trains stopped in the middle of a workday. And long lines formed at A.T.M.s and grocery stores, where credit card readers stopped working.

By Tuesday morning, the outages were mostly over, but their cause was still under investigation.

Here’s what we know.

Power has mostly been restored to the region.

Spain’s national power company said early Tuesday that nearly all power demand in Peninsular Spain was being met as of 6 a.m.

Portugal’s electricity and gas supplier, REN, said late on Monday that it had restored 85 of its 89 substations and switching stations powering that country’s grid. But some regions were still in the dark, including the coastal city of Portimão and a densely populated area south of the capital, Lisbon.

The electrical grid operator in France, where the outage briefly affected households in the Basque region, said all power had been restored.