I was returning to my home in Kennewick, WA, after delivering Christmas gifts to relatives in southern Idaho. It was early evening (around 5:45 pm), and I was driving in the westbound lanes of I-84. I had encountered heavy, thick fog at the top of what is locally known as "Cabbage Hill". It also began to snow. The roadway was snow-covered and slick. Traffic was moving quite slowly (20-30 mph). Trucks were moving especially slow due to the steep roadway, poor visibility, and slick roads. Traffic was backing up. There were 5-6 vehicles, including mine, travelling as a group, with 2-3 in the left lane and 2-3 in the right. The westbound lanes make a sharp turn to the right, straighten, steepen their grade, go through a cut in the hillside, and make a turn to the left, crossing Patawa Creek. This was in the vicinity of milemarker 222. There is a guardrail alongside the exposed side of the westbound lanes when they are not protected by embankments. As we were driving on the straight section between the curves, I could see the brake lights of the vehicles in front of me come on - the red glow getting brighter. I assumed we were either getting closer to the left turn and people were slowing, or there was some slower moving trucks ahead. I was in the left lane, and slowing down, putting more space between me and the car in front. Suddenly, I saw a large creature sitting/leaning on the pavement side of the guardrail - this would be to my left. It appeared to be watching/waiting for traffic go by. It's head turned from side to side, but I didn't notice detail. I looked at it as I drove by, and noticed that it appeared to be covered by long hair, or a long fur-like coat, which was covered/streaked with snow. It watched me drive by. At first I thought there must be an accident or stalled vehicle ahead (there were none behind me that I had passed), because why would someone be standing/sitting in that location, watching traffic? I was puzzled by what I saw, and noticed there were no vehicles stalled/parked below the location, either. The more I thought about it, the more I realized this was crazy. Why would someone be there? Except for the interstate, this spot is fairly isolated; farms/ranches are quite a long distance away. The terrain is very steep and rugged. The weather was quite cold, damp, inhospitable. If this was a "person" stranded or seeking help, he/she/it did nothing to atract attention or to get someone to stop. This was definitely not the time or place one would encounter someone out for a leisurely "stretch of the legs". I don't disbelieve in Sasquatch. I know there will always be hoaxes, and logical explanations for things that seem unexplainable. But I also know there are things yet to be "discovered", and new discoveries are made regularly. The more I thought about this, the more I began to think that maybe I did see what my second reaction said I saw. I called my wife on my cell to tell her. She got a big kick/laugh out of my story, said something about maybe I've been driving too long and should take extra care in travelling the remaining distance to home. When I got home, I retold my story to my family/friends. That "understanding" smile has been the usual reaction. But some have also said, "Who knows? Maybe you did see Sasquatch!". I finally convinced myself to report this to your site. Maybe I'll discover I wasn't the only one to see something extraordinary that night.