Today's extreme weather is causing problems at Pearson airport, on the roads, and on transit this morning. Here's the latest on what we've gathered so far this morning

Pearson airport It's a mess, see story here. A massive backlog processing passengers and luggage on arriving flights caused the airport to issue a ground stop Tuesday morning, which means no new flights can arrive at the airport until 9 a.m. ET Arriving passengers are waiting hours to deplane, then waiting again to get their luggage. We've got a live blog here, and story with links  about where you can get airport information.    

The TTC Today's -20 C temperatures are causing problems for streetcars. The culprit appears to be frozen switches, but cold weather also affects the braking systems.  

On some routes, buses are running in place of streetcars. You can check here for real-time info about bus arrival times.

GO Transit There are a few problems on GO Train routes this morning. A weather-related brake issued caused problems on the Kitchener line. Also, a delayed Canadian Pacific freight train at Milton station caused problems for the Milton to Union Station route. Go posts all delay information here.