During the time of the Rune Poem, a properly kitted warrior owned a decent war horse to take to battle. These were bigger horses than the usual so they could handle a person wearing heavy armor, and they could even bite and fight with their hooves. With the right war horse, you can be unstoppable. Almost. What can stop a war horse? Ice. Ice is brutal for horse hooves. It can ball up under their feet until they are teetering on their own personal ice cubes. Have you ever fallen on ice? That’s not a soft landing. A horse can easily slip and break a leg on the frozen dips and grooves in a road, and if they fall right through a frozen lake or river good luck getting them back out. Have fun with that. A war horse, large and powerful, formidable in battle, is handily defeated by ice.