London Heathrow Airport will be closed all day due to a power outage, causing global flight chaos

• Heathrow Airport will be closed all day Friday after a nearby fire caused a power outage.
• Heathrow is advising passengers not to travel to the airport and to contact their airline for more information.
• More than 1,300 flights are expected to be affected.

London's Heathrow Airport, one of the world's busiest, will be closed through Friday after a large fire nearby caused a "significant power outage."

Flightradar24, a live flight-tracking platform, told Business Insider that 120 flights already in the air are expected to be diverted from the airport. The platform said at least 1,351 flights would be affected.

The airport advised passengers not to travel to the airport and contact their airline for more information. Last year, 83.9 million people flew through Heathrow, up 6% from the previous year.

"Due to a fire at an electrical substation supplying the airport, Heathrow is experiencing a significant power outage," the airport posted to X early Friday morning local time.

"To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23h59 on 21 March."

A spokesperson for British Airways, one of the airport's main airlines, said in a statement to BI that this would "have a significant impact on our operation and our customers."

"We're working as quickly as possible to update them on their travel options for the next 24 hours and beyond," they added.

The airline is redirecting flights already on their way to Heathrow to other UK airports, the statement added.

The fire is at an electricity substation in Hayes in West London, about 1.5 miles from the airport. The cause of the fire is not yet known.

The London Fire Brigade said in a post on X that 10 fire engines and about 70 firefighters were called to the scene of the fire.

Images show large flames and plumes of thick black smoke. Local media reported that tens of thousands of homes in the area are without power.

Around 150 people have been evacuated so far and a 200-meter cordon is in place, the London Fire Brigade said.

"This will be a prolonged incident, with crews remaining on scene throughout the night," the Brigade wrote on its website. "As we head into the morning, disruption is expected to increase, and we urge people to avoid the area wherever possible."

London has several other international airports including Gatwick, the city's second-busiest airport, and Stansted, known for budget flights and flights to Europe.

Do you have a story to share about how your plans are affected by Heathrow's shutdown? Contact reporter Pete Syme at psyme@businessinsider.com.