The Arden Buck equation is a mathematical formula that is used to predict how much water is in snow. It uses two different measurements to calculate how much water is in the snow: how much snow has fallen, and how much of the snow has melted. To get the answer, you first multiply the amount of snow that's fallen by how much of it has melted to get the total amount melted. Then, you divide the total amount melted by the amount of snow that first fell, and that gives you the amount of water in the snow.