Deluge

Merriam-Webster says:
Deluge -- "A large amount of rain that suddenly falls in an area."

Others say:
Deluge -- "A poor circumstance in which to pack a vehicle for cross-country travel, especially in the dark of the night."

or:
Deluge -- "A psychological stimulus known to significantly diminish regret associated with departing all locations in Washington State lying west of the Cascade Mountains."

or:
Deluge -- "A highway phenomena known to drastically increase the probability that an animal-laden minivan will hydroplane into the median of any randomly chosen roadway."

or:
Deluge -- "A rather annoying way to start a cross-country road trip."