How to pronounce “steepness” in English

So the genius in Lagrange's idea is this.At any given point, we can draw an arrow pointing directly downhill where the size of the arrow corresponds to the steepness of the hill at that point.We can repeat this process at every point, and if we then shift our perspective to two dimensions, look, what we've got is the gravitational field of the star.

One person made the summit that year from another team, a Russian guy.Now it's on to the Lhotse Face-- this 3,000 foot wall of ice, 45 to 70 degrees in steepness,