Preliminary reports out of Europe about the massive blackout that left millions powerless suggest that the cause may have been "induced atmospheric vibration," a rare phenomenon where weather changes affect power lines.
The outage was centered in Spain on Monday, where the lack of power caused widespread chaos. Renfe, Spain's national railway company, said on social media that the "entire national electricity grid was cut off" at 12:30 local time.
This blackout brought parts of Spain and Portugal to a standstill, grounding planes, halting public transport, and forcing some hospitals to suspend routine operations.
Portuguese energy company REN suggested that "due to extreme temperature variations in the interior of Spain, there were anomalous oscillations in the very high voltage lines (400 KV), a phenomenon known as 'induced atmospheric vibration,'" according to a BBC.com report.
Spain's Prime Minister Pedro Sánchez mentioned a "strong oscillation" behind the outage but stated that no conclusions about the cause could be determined yet, Weather.com reported.
AccuWeather meteorologist Dan DePodwin explained that "induced atmospheric vibrations" are rare but can occur due to rapid changes in temperature or wind speed. "The atmosphere induces vibrations in power lines, leading to outages," he said.
He also noted that quick temperature changes or extended periods of extreme temperatures can trigger this phenomenon, which can occur anywhere with transmission lines, including the U.S.
The Guardian highlighted the well-known risks to electrical systems from significant temperature variations in the industry, even though problems reaching this scale are rare.
These variations can cause synchronization failures between electrical systems, as reported by Forexlive.com News.
"Due to temperature variations, the parameters of the conductor change slightly," explained Taco Engelaar, managing director at Neara, a software provider to energy utilities. "This creates an imbalance in the frequency."