OP, you also never said what airline you were booked on. If you're flying on Frontier or Spirit you may be SOL regarding much assistance from the airline in the event of a cancellation. Also, my guess is you don't have any status on the airline, which also makes a difference, like it or not. Is your flight from SEA direct to Houston, or do you stop in Denver or somewhere? A direct flight would at least eliminate the risk of missing a connecting flight if your SEA flight left late.
Anyway, good luck and safe travels.