KANSAS CITY, Mo. (AP) – Heavy snow has forced the closure of the Kansas City International Airport.

Airport officials announced on Twitter shortly before 10 a.m. that the whiteout conditions had forced the airport to shut down. Earlier, conditions had reduced air traffic to a single runway, and maintenance workers were having trouble seeing each other through the blinding snow.

It wasn’t certain when the airport would reopen and how many flights were affected. Travelers are being urged to check their flights frequently and monitor local media before making the trek to the airport.