Screaming or howling in Skamania County, Washington

I had backpacked into Deadman's Lake for a one night stay. It was during the Washington bow season for elk. As I was heading in I ran into two hunters on the trail hunting down to their vehicle to dry out and stay in their camper. They told me that a group had been hunting in the area but had to leave because there horses were acting up. As I got to the lake I could tell that the horses had been kept in a small meadow near the campsite area. I pitched my tent in this area. I was at the lake doing a little fishing before dark when I heard a howl way off in the distance. I didn't think much of it, it was miles away. There were also several bull elk bugling in the hills behind the lake and at one point I could hear some cow elk "talking". Being an elk hunter myself, I am very familiar with the sounds elk make during this time of year. That was one of the reasons I had gone to this area was to try to call in and get pictures of the elk. As night fell I stayed up until approximately 9:00 PM listening to the sounds of the woods. I could hear a couple owls hooting back and forth across the lake as I fell asleep. At 11:24 PM I was awoken by the same screaming howl I had heard before but it sounded like it was coming from the meadow I was camped next to, about 50 yards away. It sounded like a cross between a wolf and a very loud human. It sounded as if it were a hailing call. I opened the front flap of the tent and grabbed my light and the only weapon I had, my knife. I also grabbed the camera just in case I could see something. The howl had also scared the two owls I had heard hooting earlier that evening. The owls continued to call back and forth to each other for a time after that but I never heard the howl again. I stayed awake for hours after that and eventually was able to relax and get some sleep. I woke up that morning to the sound of bugling elk and when it got light enough I went to look for any sign of what I had heard the night before. I found a herd of cow elk by the lake but nothing unusual. The weather started turning about this time so I packed up my stuff and headed back to my car.