These aren't the best screenshots I've taken, mostly because it was almost impossible to properly frame this mountain and still have it at all convey the height and steepness of it. Unfortunately the planet was so hazy that taking a picture from the top didn't really convey that (along with NMS's draw distance).
If you look at the second shot, that ledge above the triangle rock actually has a full beacon and crates scattered around, so that might help discern the scale of it a bit better. And if the triangle is pointing up, I'm going to say the mountain has an incline of about 75 degrees? Steepest one I've seen in NMS, and honestly it felt like the tallest mountain I've climbed in a game.
Also, I love the rock formations on this planet. So many interesting shapes, and many of the rocks (like the cool pyramid-shaped ones) were almost pitch black. If this wasn't radioactive and filled with giant crabs and tentacle brains, I might build my base here.