People lose their jobs, have medical emergencies, get divorced, pass away or make bad money decisions at a certain rate. Because of the rise in home values, much of that financial distress has been covered by the increasing amount of equity that people have had in their homes.
Trends in January and February are notoriously bad at predicting upcoming activity. Is the market taking a breather? Or is it starting to tumble? It's impossible to say, there's nothing really ominous in the numbers, but we won't know for another couple of months.