We spent the last four days camping here, along this lake. The lake is called Diablo Lake and is located in North Cascades National Park. The weather was gorgeous and my children are now old enough to do one short hike per day. The thought of taking a dip in the lake following a hot hike was tempting, but this lake is glacier fed and quite chilly. I did take a short swim in it when we camped here about three years ago. I remember feeling all of the blood shunt to my heart during that dip and it was a little scary. I didn't immerse myself this time.
We hiked down and saw Ross Lake Dam on this trip as well. For more information about this natural paradise visit http://northcascadesnationalpark.com/.