Screaming or howling in Yakima County, Washington

While on a family camping trip this summer, my husband, our two teenage boys, and our two Newfoundland dogs headed out towards Naches where my husband often hunts. We don't like "organized" camping, so we headed towards Bumping Lake in the Mt Baker/Snoqualmie National Forest. We had got a late start, and arrived at the lake about 8:00 pm. We continued on past the camping area at the dam about 4 or 5 miles towards the "Deep Creek" area, hoping for a secluded camping spot by the lake. We turned off on a four-wheel drive trail about a mile from Deep Creek. Found a campsite next to a swamp, and as it was getting late and almost dark, we decided to camp. After setting up camp, about 10:00 pm, our dogs went absolutely nuts, barking and very excited...a few minutes later, a car arrived looking for a camp site, but turned and left. The dogs definitly heard this car well before we did, and did their job annoucing the presence of this "intruder." We fired up the campfire and ate a late dinner, while getting comfortable with our surroundings. It was a mild night, it had been hot and dry for some time. About midnight our two boys headed off to bed. Our big male Newfoundland was chained to a tree about 5 yards away from the campsite. Our female Newf was at our feet, as usual. It was extremely quite where we were. My husband and I were sitting by the campfire relaxing when, out of the swamp beside us, not more than 100 to 200 feet away came a noise, a screem or a grunt that changed pitch to a screech and then ended in a grunt-huffing sound, lasting a long time. The dogs had not reacted at all until they heard this scream, when they went wild. My husband is a logger and advide hunter-outdoorsman, so I turned to him and asked "what was that?" From the look of his eyes and on his face, I knew that he did not know what it was. He has heard the voices of about every animal in the Pacific Northwest at some time in 30 plus years of being in the woods. Our oldest son came out of the tent and asked if "someone was messing with us." He thought it sounded very human-like. Please remember that there was absolutely no noise, ie sticks or brush breaking or moving prior to the scream, and the dogs didn't detect anything around us, and they were extremely on edge in their new surroundings. We got the dogs settled down and began discussing possibilities of what was out there. All was quite about 15 minutes later, when we heard what sounded like two sticks being hit together about 100 yards north of the original scream. The dogs once again went nuts. About another 15 minutes went by when we heard this same noise of sticks being hit together, this time farther away, about 300 yards north and the dogs once again did their thing. Whatever it was had moved silently through the brush in the swamp, apparently downwind from us as the dogs detected no movement between the noises. About an hour later we found ourselves in the middle of a dry-lighting storm and heard no more unusal sounds. The following morning my husband and sons went on a search of the area and found no tracks or broken brush around the swamp. We promptly packed up and moved to Deep Creek!