Far, far to the south, where east and west meet and become north, there is a valley, carven not by the slow slide of the world's rocky skin over her firey heart, but rather the wind and water have carven it, deep and narrow, folding away from the sun. Here, at its deepest depths, the Light never reaches. Here, at the top of the bottom of the world, lies the place which Shadow and Darkness have dedicated to themselves.
Rain slowly builds, thunder and lightning continue to roll in. Road muddies, horse/wagon getting stuck in the mud. Thunder strikes coinciding with a deep hole a horse just walked in, horse panics, breaks its leg (maybe just sprain?). Horse is decompacitated and the rain just went from pouring to an all out monsoon. Shelter needs to be found, horse needs to be taken care of, covered in mud, add the posibility of items being lost to the confusion with the wind and dealing with spooked animals.