I learned, a few years ago, to not ride the South Platte Trail during certain Spring and Summer months.
I had always known that bugs could be a problem on that trail. I grew up around rivers and lakes, down south, so I am familiar with how the insect crowd loves the shoreline. But, I never experienced the sheer number of bugs per liter of atmosphere that you can find along the South Platte Trail.
I left my house, one afternoon, to take a quick ride down to Chatfield Dam, and back. I was living on Sherman Street, at the time, and the ride to the top of the dam and back was about 25 miles. It made a nice little "stretch my legs because I haven't been riding enough, lately" kind of ride.
I rode the streets to the west side of the river, then turned south on the trail. As I rode along, I noticed a few gnats in the air. I didn't think much about it. Then, a couple of miles south of Highway 285, I looked ahead and I could see what looked a cloud of smoke hanging over the trail.
I entered the cloud and realized that it wasn't smoke. It was gnats!
I pressed my lips together, and tried to not breath too deeply through my nose. Still, a few got into my nostrils and I had to sneeze them out.
I cleared the swarm, and thought to myself that I didn't relish having to run through them, again, on the way home. I was hoping they would be gone, by the time I headed back.
Then, I saw another cloud up ahead. Dammit!
All told, I probably ran through a couple dozen of those insect clouds on the way down to the dam and back. Luckily, I had a bandanna with me, and I was able to wear it as a mask and keep the infernal pests out of my mouth and nose.
But, by the time I got home, my hair was lousy with them (pun intended). I showered, and combed the bastards out of my hair as I shampooed. It took two shampoos before I stopped getting combs full of bugs out of my hair. (And, my hair was short, not over 1-1/2 inches long at any point.)
I avoid the South Platte Trail during the fishing season, now...