Spain, along with Portugal and parts of south-west France, lost power on Monday (April 28) after a “rare atmospheric phenomenon” caused unusual oscillations in high-voltage lines, leading to a frequency imbalance across the grid.
The power failure caused mass outages for telco services, with both communications and infrastructure impacted.
Vodafone Spain fired up its backup generators, with its mobile network temporarily down to 70% active around midday. By 11 pm, 60% of mobile traffic was restored, with service set to gradually return in line with power coming back online in some towns and regions.
The operator confirmed that all of its control centres, including its data centres and other systems, remain operational with sites holding “sufficient autonomy” until power is restored.
“We continue to recommend responsible mobile phone use to prevent network outages,” Vodafone Spain said in a post on X (formerly Twitter).
Telefónica launched its Crisis Committee, which looks to maintain service during emergency situations, like the catastrophic flash flooding in Valencia, Spain, last November.
On the morning of April 29, the operator said that over 90% of its fixed and mobile services have been recovered, with the firm maintaining all services identified as essential.
“The company continues to work towards full normality in Spain,” Telefónica said on X.
MasOrange said it has restored more than 90% of its services by the following day, with the company working to restore them to 100%.
Along with telco services, internet traffic plummeted on the day of the outage.
Data from Akamai observed a roughly 75% drop in internet traffic from users in Spain and Portugal on April 28, more than the roughly 50% drop in electricity demand in Spain at the same time.
“The outage shows us that while physical infrastructure can still be fragile, modern distributed systems continue to get stronger at keeping digital life going – even in the face of massive disruption,” said Jon Alexander, SVP for cloud technology at Akamai.
Rumours quickly circulated online suggesting the outage could have been the result of foul play, such as a cyberattack or an act of cyber terrorism.
While the exact cause is still under investigation, Spain’s prime minister, Pedro Sánchez, urged the public to avoid spreading misinformation.
Authorities currently attribute the outage to a rare atmospheric phenomenon that triggered sudden temperature swings, causing high-voltage transmission lines to oscillate abnormally.
Portugal’s national grid operator said in a statement:
The resulting disruption to the delicate balance between electricity supply and demand caused a frequency instability, triggering a cascading failure across the Iberian Peninsula.
Outages on this scale are extremely rare — and those triggered by weather events are rarer still.
In 2003, a failure on a hydroelectric power line between Italy and Switzerland plunged much of the Italian peninsula into darkness. More recently, in 2021, a winter storm caused widespread power outages across Texas.
Another high-profile power outage, which took place earlier this year, saw London’s Heathrow Airport shut for 24 hours after a fire at a nearby electricity substation left thousands of passengers stranded.
