My girlfriend and I were staying on a friends property near Glendale, UT. We were just off of Highway 89. Last night It was very windy and I woke many times. I was lying in our sleeping bag when I heard something coming down the canyon. It sounded very loud and very low. It was a deep, constant hum. It got closer and closer at a very steady pace. As it neared it drowned out all other sound, including the shaking of our tent from the wind. I wondered if I spoke, would I hear my own voice? It never slowed and just kept moving down the canyon. It seemed to drag a wake of pleasant weather. There was no wind for a minute or two and the entire canyon was quiet. I couldn't hear a single car on 89. I thought of the eye of a hurricane. The storm gradually crept back in. I heard a truck flying down the highway through the shaking of the tent and the wind through the scrub oak. I eventually fell asleep. I can not think of what could have possibly flown over us last night. It was far too slow to be a plane and the sound was low and sustained, completely unbroken, unlike the chopping of a helicopter. I saw no light at all. Today, on the drive home I told my girlfriend about it, I thought she had slept through it. She said she remembered it all and was too afraid to move.