Flight delays and cancellation happens during a snow storm. Separation between airplane has to increase and airplanes are moving slower on the ground, just like you would drive slower on the roads during the storm.
The day after the snowstorm not all planes are in their correct starting position due to cancellation or diversion. Now the airline has to find a open plane, pilots and flight attendants and they may not even be at your airport. The crew will need to re-position to your airport.
Too try to help alleviate the delays, they won’t re-position it empty. If there is a flight scheduled out of their position it will be assigned to them.
In the end this is how the flight board will look mostly delayed.