A lightning strike during Thursday afternoon’s thunderstorms knocked out power at Pittsburgh International Airport, disrupting dozens of flights and temporarily disabling both the airport’s main electrical supply and its backup microgrid.

The airport said service has since been restored, but some flights remained delayed as crews worked to return systems to normal.

“Systems are coming back online and flights are departing and arriving,” airport spokesman Bob Kerlik said in a statement. “Teams are continuing to manage the situation and update passengers in the terminal.”

Both the main grid and the 23-megawatt microgrid – a backup power source designed to operate in “island mode” in the event of a wider outage – were knocked out when lighting struck Duquesne Light infrastructure around 3:30 p.m. and caused a large power surge, Kerlik said.

Kerlik said power was partially restored within an hour and credited the backup grid’s performance.

”If we didn’t have the microgrid, we’d probably still be out right now, or at least partially out,” he said shortly before 7 p.m.

Several dozen flights were still listed as delayed on Pittsburgh International’s website as of 5 p.m., and Duquesne Light reported more than 35,000 power outages.

Kerlik said the airfield and air traffic tower were not affected during the storm and maintained power throughout, meaning that planes were able to land and take off. Two cancellations Thursday afternoon — one flight to New York City and one to Chicago — ground stops due to storms in those locations and unrelated to Pittsburgh’s weather, he said.

“We appreciated the patience of our passengers as our teams, along with our partners at Duquesne Light, worked to restore our systems and return operations to normal,” he said.

Puskar advised passengers to check with their airlines regarding flight statuses and plan for extra time at TSA. Standard TSA lines had 47-minute wait times shortly after 5 p.m., while PreCheck wait times stood at 10 minutes. Wait times were down to 2 minutes in Standard by 7 p.m., and there was no wait for PreCheck.