Not only snow and fog are interfering with air travel this winter.
The power is back on at Reagan National Airport after an hour-long outage that brought flights and security screening to a standstill.
Power was out from about 12:30 p.m. until 1:30 p.m., said Courtney Mickalonis, a spokeswoman for the Metropolitan Washington Airports Authority.
The Transportation Security Administration was able to quickly resume screening using a backup generator at two of four checkpoints, but some flights were affected.
The airport control tower has a backup power source, Federal Aviation Administration spokeswoman Diane Spitaliere said. The FAA barred planes from landing during the outage because power jet ways weren't working and there was no way to unload passengers at the terminal. Departures weren't halted.
Mickalonis said delays could persist throughout Monday afternoon and advised travelers to check with their airlines before heading to the airport to catch a flight.
The problem originated at an airport substation, Mickalonis said, but the cause of the failure is still under investigation.