Professor Cumulus Isobar
Photo Credit - WDW Guided Tours - WDWGuidedTours.com
It passes by so quickly it's difficult to see, but just before you roar past the flooded town of Tumbleweed and dive into the Dave V. Jones Mine, look left and notice the wagon of Professor Cumulus Isobar, Rain Maker. Look quickly, and you'll find the professor himself leaning out the front door while bailing out his wagon, all while his two donkeys stand to the side high and dry. His name, of course, is a nod to the Disney Imagineers' sometimes whimsical nature, as "Cumulus" is a type of cloud and "Isobar" is a measure of barometric pressure.
Author's Tip: The scene of Professor Cumulus Isobar flies right by as you're riding Big Thunder Mountain Railroad, but if you'd like to see a slower perspective of Big Thunder Mountain and get a shot similar to the one above, then hop aboard the Walt Disney World Railroad at the Main Street or Frontierland Stations.