There are multiple reasons bees swarm. First and foremost, lack of space for the Queen to lay. As we become better Beekeepers, one of our first benefits are strong colonies coming out of Winter. In Texas our "Honey Bee Spring" starts in February.
Doing a quick hive inspection on warm days beginning the first of February is essential for circumventing swarms. You will notice that the stores that encompassed the previous Fall brood chamber are now being back filled with brood. This is your sign! Consider 1 of 2 options...Either add an additional brood box on top (with at least 4 center frames of drawn comb) or prep to make a split.
February is the number 1 month bees starve! Feed your bees if needed.