El Nino Watch: Trail Damage and Riding after it Rains

We are having a severe El Nino event this winter; as a result the weather forecast is for many heavy rainstorms in the early months of 2016. That will help our drought situation, but will have seriously bad impacts on our trails. As well as muddy conditions that interfere with their use, described  below, the rains could be severe enough to erode some trails into huge ruts, and even wash them away in some cases. There may be more mudslides in Pt Mugu State Park (Sycamore Canyon) like we had last year. Furthermore, the rain will spur the chaparral to overgrow the trails, a condition we haven’t had to deal with much over the past couple of years because of the drought. The combination of waterlogged soil and high winds could blow trees over. We’re expecting to have special trailwork days to repair these damaged trails and hope many mountain bikers will want to help us get them back into shape!

Most trails in our local riding area don’t respond well to rain. They have a high content of clay that turns into sticky, slippery muck that binds to everything it touches. It builds up on the tires, like a snowball rolling downhill, until it jams on the frame and the wheels won’t budge. Some models of clipless pedals won’t let go when full of this mud, resulting in the bike and the attached rider lying sideways in a puddle, or worse.

Most wet trails don’t respond well to use until they’ve had time to dry out. Hikers and horses make holes and ridges in the trail that become as hard as concrete when the trail dries. These holes and ridges are good for twisting ankles.

As a rule of thumb, if your foot, tire or hoof makes an impression more than about 1/8 inch deep in the dirt, the trail is still too soft to use. Give it another day or two to dry out before using it!

On wet trails, bikes make grooves along the trail. The next time it rains, the water runs down these grooves and turns them into little ruts, then large ruts that destroy the trail.

The mud is particularly hard to remove. It sticks to the bike and shoes, no matter the efforts to remove it, rubbing off on the bike rack, car carpet and gas/brake pedals, making them slippery. Once home, it takes the careful use of a garden hose to remove the mud but not force water into the sensitive parts of the bike.

For these reasons, riders are well advised to stay off the trails after a rain until they have dried. How long to stay off? That depends on a number of factors including the particular trail, how much rain it received, how much sun it gets after the rain (is it in the shade or face south?), how warm and windy the weather is, and so on. After an isolated light rain you can probably ride the next day. After a heavy rain, you should wait several days. This is something where common sense and experience will help. Remember, tracks deeper than 1/8″ mean the trail is still too soft to use!

All is not lost when the trails are soaking! There are a few trails that hold up well when wet because they have more sand and rock that doesn’t hold the water. Here are a few you should know about:

Space Mountain (Los Robles Trail West) to the picnic table is almost always rideable, even right after a big storm. However, it can be pretty mucky from the picnic table to Potrero Road.
Rosewood Trail is pretty good, but not quite as resilient as Space Mountain.
Zuma Ridge Motorway from Encinal (the bottom in Malibu is muddy)
Dirt Mulholland around Topanga State Park.
-Brown Mountain Fireroad
-Most San Gabriel Mountains trails made up of decomposed granite
-Beaudry Fireroad
-Hostetter Fireroad
-Mt. Lukens

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