First: That Grus forms on boulders and is detached from the boulder it has formed on before it falls to the ground.
Second: Falling off the top of a six-foot boulder is not nearly as painful as the sudden stop at the end of the fall is.
Here's how it all went down (Pun intended): I went out bouldering in Boulder Canyon last weekend. It is a wonderful workout and a great way to see what there is to be seen of this lovely area that I live in! For those of you who do not know me well, a few years ago, I became aware of the sport of bouldering. Unlike free climbing or technical climbing, bouldering is a sport that calls for no special equipment and not a lot of physical fitness. It is a great place to start climbing.
In bouldering, you go to a mountain that has a lot of projecting boulders and you climb them. Usually, the boulders are no more than eight to ten feet individually, but since they are in piles, they can be bigger provided they lay against each other in such a way as to make climbing without equipment feasible. The object is to find a pile of them that is big enough to present a challenge but small enough that you can still get your arms around them, your feet and legs to places where you can lift yourself, and you then go for the top!
Map of Boulder Canyon
Well, I had made it to a pinnacle that I like to go to. It is about a mile from where you park your car and then a climb equivalent (from base to summit) of about a three-storey Building. The climb is not that strenuous, but by the time I reach the top, it is time to take some water and enjoy the view. It was on my way down that I learned my lessons.
The climb has two approaches. One has a few relatively hard climbs of eight to ten vertical feet interspersed with some nice sloping dirt paths in between and plenty of places to rest. The other side, the one overlooking the canyon is pretty much one long climb with a few ledges that are wide enough to stop on and to take a break and a look at the breathtaking views. Generally, I go up the steep way and then back down the easy way. It was no different this past weekend. I made the climb up the steep side, and enjoyed about an hour-or-so of staring out at the canyon below. (The entire descent into the canyon, all the way to the river, is easily as tall as a forty-story building. It looks as far from where I like to sit and enjoy the view to the river, as it would be from my office to the street. However, I only climb the top part from where the parking area is to the top. I have toyed with the thought of climbing down and back up, but the people I see do that all use harnesses and ropes and are far more fit than I am. It is sheer!)
On the way back down, I was at the last of the climbs before I was at the path back to the parking area when I jumped onto a grus-covered boulder. Of course, I didn't know it was covered with grus when I jumped onto it. Since grus is nothing more than degraded granite, it is granite colored and looks just like granite. It felt like granite underfoot. It was only when I went to jump to the next boulder that I discovered its true nature.
I was standing there contemplating which of the boulders ahead of me I wanted to go to. I could either make a pretty long (for me) leap to another boulder that was about two feet lower than the one I was on, or I could sit on the one I was on and slide down its side to another one that was about four feet lower than the one I was on. I opted to make the jump. This was a mistake. The boulder I was on had a surface of grus that had felt just fine when I landed. It felt fine as I stood there. The moment I applied lateral force to it to make it across the gap to the next boulder it gave way and went shooting off the rock behind me.
The first law of motion (or perhaps inertia is the first law and this is the second… I can never keep these straight) is that for every action there is an equal and opposite reaction. The hope in this leap was that the force that I would need would be imparted to a steady and stable rock and that I would be propelled across a gap of open air landing safely on another boulder about three feet away. The problem is that the only action of thrusting my entire weight against the boulder (pushing with my legs in a direction opposite the one I wished to be propelled) never actually occurred. Instead, my action was to push a few pounds of grus, now loose (there’s a grus on the loose!) from the top of the boulder allowing it to fall to the ground. As this is hardly enough of an action to accomplish the desired reaction (my flying across the gap) I was left to react to the meager action I had created. Far from being enough to carry me across the gap, the momentum was sufficient only to carry me off the top of the boulder. I slid down the side and came to a rest at the bottom of the boulder twisting my knee painfully in the process.
I was not really hurt so I picked myself up, brushed myself off and walked (albeit a bit slowly and with some small amount of pain) to the car. The car was not that far off, about a mile, I guess, and it was luckily mostly level ground as long as I circumnavigated a couple stacks of boulders. And it really didn’t hurt too much when I drove home. Monday morning was another issue. The pain was exquisite! I have already had an X-Ray. There is no bone damage.
Yesterday I had an MRI. That was an unpleasant and painful experience, but that is another story. I feel better today and can almost walk without the aid of the crutches!
I hope your weekend is safe and sure-footed!
Don Bergquist - 26-June-2005 - Lakewood, Colorado