A few nights ago gusts of wind were blowing out across the arm at nearly eighty miles per hour. They broke into Fresh Air on NPR with the emergency broadcast beeps. I spent most of the night peering warily out windows at the tall trees outside and watching the air become opaque with windlofted snow. The whole house creaked and the doors swelled and groaned against their frames. It went on for hours, and I never did get to sleep. By early in the morning the wind calmed and it began to snow; I took a book and a cup of coffee and got in the tub.
At first light I went out and walked my regular circuit. Limbs were down everywhere. The snow was blown and swirled against trees and creeks and it had drifted over the trail in some places as deep as I am tall. It had been ground into powder so fine that, even in shoeshoes, you had to hike up and around. But it was snowing though the post-storm stillness even as I walked–all of this upheaval and desolation was being covered in inches and inches of fresh, white, soft, brilliance. I left the only pair of tracks as I passed, and everything was hushed except a raven I spotted in a tree almost directly overhead. He raked his feathers up and made the strangest noises: at times they sounded like a baby crying; at times they sounded like the percolating ponks of one of those big metal coffee makers. When he flew away he rustled the top of the tree and I was pelted by the large clumps of snow that cascaded down.
Something else strange happened as well. Perhaps it was the sleepless night or my surroundings that spawned it, but on the way back I became intensely aware of my animalness. It began with the odd sensation that I could feel the bones in my feet as I walked; that I could feel them working against each other, and then I felt that they were bound by ligaments. I could feel muscles pulling. I could feel the tendons that tun up the backs of my legs. And then after just a few more paces it was everywhere.
I was aware of my ribs flexing gently as I breathed. I could hear a barely perceptible squeak from the cartilage between the vertebrae in my neck when I turned my head. I could feel the surging of my blood, and tickles of electricity that danced around in my head with every new sensation.
Nothing like that has ever happened to me before. For perhaps ten minutes I was completely aware of the biological machinery of my body. I was transfixed. I had the palpable feeling of being alive, and it was joyous but also frightening– there was nothing evident in that perception to assure me that any of these cycles and mechanisms would continue for a moment longer. There was nothing I could do but to muster all of my attention for it and to plainly and brazenly wonder.

Some people meditate for years in hope of achieving some shadow of the awareness you describe so vividly in this essay.