Spanning 40 degrees of latitude, some 4,800 kilometres (2,980 mi), the Rocky Mountains run the length of North America from the Liard Plain in the north to the Rio Grande in New Mexico. 
The river systems that gather and wind their way out of these mountains head in all directions. Vertically, they soar above 14,440 feet (4,401 m).

Four individual raindrops hitting their highest peaks could easily end up thousands of miles apart -- one flowing north to the Beaufort Sea, another reaching the the Gulf of Mexico, a third would be absorbed into Hudson Bay to the east and the last into the vast Pacific.