All I can say is wow! This Trail starts off at a nice gentle slope for about 1 mile, after that be prepared for some serious altitude gain. I did this hike in May 2018 and the mountains surrounding the trail were still covered in snow. there was a small river running across the trail which require waterproof boots and some careful footing. If you're looking for a real leg workout about halfway up you will come across a set of railroad tracks that were used for a pulley car to haul supplies up to the dam. You can take this track up to the dam but your legs better be in excellent shape. I measured a 37 degree incline.
I continued on to Gem Lake and it was worth the extra time and effort.