Scientists believe this happened because it's springtime on Titan, and that means weather patterns full of rain. Of course, since Titan's colder than a Hillary Clinton look at Bill in early 1998, it's not water rain. Water is ice on Titan's surface. The rain is liquid methane, as are the different lakes and small seas scattered here and there on the moon's surface and the clouds that sometimes cover it. Methane, in fact, takes the place of liquid water and water vapor in Titan's weather system, scientists believe.
Since it's so cold, though, a storm on Titan would be pretty much instantly fatal if you were caught out in it. Assuming you survived longer than a couple minutes of breathing methane gas and the couple-hundred-below zero temperatures, that is.
One may note, if one wishes, the irony of the fact that a storm which really could kill us all exists without harebrained local weather nitwits to vamp for ratings by claiming the storm which they have been broadcasting for the last 90 minutes could kill us all.