Winter Trail Information & Riding
Why are ruts bad for trails?
Expanding ice crystals loosen the compacted trail surface creating cavities that trap water. Result: a pudding like mud when thawed.
Ruts in a trail collect and channel water causing increased erosion of the trail surface and trap water which slows the drying process after rain events. Trails are built with outslope to shed water much like a paved road. Ruts disrupt this water shedding action and can allow water to flow along, instead of across, the trail. Concentrated flowing water following the ruts, typical during heavy spring/summer rains, can then pick up soil particles and wash them away. This can leave behind deeper ruts tens or hundreds of feet long in extreme circumstances.
Ruts and footprints also hold pools of water on the trail surface which causes saturation of the soil and greatly slows drying. If these puddles are disturbed by users they can quickly turn into large mud pits. People naturally try to avoid the mud by walking/riding around the puddles which only makes the mud pit grow wider and harder to repair. Fixing these areas eats up trail volunteer time that could be better focused on other projects. Wet areas like this also greatly prolong trail closures since they dry very slowly. Ride/walk through the middle of a mud pit for the least trail impact.
What are freeze thaw cycles and how do they affect dirt trails?
Freeze thaw cycles refer to the thawing and refreezing process soils experience during colder months. Air temperatures hovering around freezing and variance in solar irradiance throughout the day are the driving factors for freeze/thaw cycling. Dirt trails are extremely prone to rut damage during the transition to/from winter because of this process. During freezing, soil particles are forced apart by expanding ice crystals which essentially de-compacts the trail bed. When these ice crystals melt with warming daytime temps these small spaces fill with water and form a very liquid like mud. Trails in this condition have almost no mechanical strength to support the weight of users. Water logged dirt the consistency of pudding or peanut butter is not uncommon during the spring thaw. It's very easy to make deep ruts when the dirt is in this condition since the frost de-compacting action can reach several inches in depth.
Frozen footprints left in a trail after a midday thaw.
Footprint ruts hold water causing the surrounding trail to stay wet and closed longer. They are also very time consuming to repair since a single user can create hundreds of impressions in a matter of minutes.
Do freeze thaw closure conditions ONLY apply to bikes?
No. Both bikes and foot traffic have negative impacts on muddy trails. The ground pressure exerted by walking is nearly the same as a rolling mountain bike tire and can cause similar damage to muddy/soft trails.
Is it OK to ride fatbikes in freeze/thaw conditions?
While fatbikes have lower ground pressures than regular mountain bike tires and even walking, they can still form ruts and degrade trails during freeze/thaw conditions. We advise against riding ALL bikes on dirt trails when conditions are not suitable.
If there is snow on the ground is OK to ride/hike?
In most cases it is OK to use trails when they are snow covered but if the ground below is not frozen and there is only a thin covering of snow it may still cause ruts/footprints. Use your best judgement and turn back if you're leaving tracks in the trail.
Tips for Riding During the Winter
Pay attention to the trail status on the CITA Trail Status page as well as the signs posted at local parks.
Don't use frozen trails when the temperature is above freezing.
Use frozen trails early in the morning before they have a chance to warm.
Don't ride if the temps are hovering around freezing and it is sunny. Wait until temps are below 28F and even then there may be thawed areas.
If after following all the above guidelines and the trails are still too soft, turn around and come back another time. A single user can damage thousands of feet of trail under these conditions.
Please respect the trails over the colder months so everyone can maximize their enjoyment come spring time. Hundreds of volunteer hours go into creating and maintaining these trails each year.
