Snowpack

One of the most frequent questions we get from Trail users each spring is “When is The Colorado Trail likely to be snow free?” The general rule is that most of the CT is snow free by early July and, except for occasional remnants at higher elevations and on some north-facing hillsides where the Trail is shaded in the trees, it will likely stay that way into September. This can vary by a couple of weeks either way depending on the harshness of the previous winter.

To be safe, we suggest July 1 as the earliest plan-ahead start date for most hikers, bikers and horse riders who plan to go long distances on the Trail. Those who start from Denver in the “iffy” month of June can expect to encounter snow, sometimes several feet deep, as early as the approach to Georgia Pass in Segment 6 and along the Ten Mile Range in Segment 7. Those leaving from Durango can expect to encounter it even earlier during their trek into the San Juan Mountains.

Following the Trail when it is buried in snow is challenging even with the aid of GPS because, frequently, you can’t see the Trail or even the corridor to follow it. Whether it’s easy or hard will vary with snow conditions and tracks laid down before you. If you can follow the exact trail corridor, because it is periodically cleared of deadfall by volunteers, the ‘going’ will be relatively easy. But it can get really hard and hazardous if you get off the Trail. And unless you are willing to add the weight of snowshoes or skis to your load, you can expect to do a lot of “post-holing,” plunging with each step up to your knees or hips in snow. Post-holing is exhausting, frustratingly slow, and hazardous – especially given the hidden uneven surfaces and deadfall beneath, it is an invitation to sprains, strains and ACL tears. Few people who have experienced it are game for more. This video shows what post-holing can be like.

Check our website for the latest information on snow depth as your trip approaches and be prepared to make adjustments accordingly. Information from Trail users posted on social media sites can also be helpful.

Another resource is SNOTEL (short for snow telemetry), an automated system of snowpack and related climate sensors operated by the Natural Resources Conservation Service of the U.S. Department of Agriculture. But beware of its limitations. A longtime CTF volunteer who has monitored SNOTEL weather stations for years points out that virtually all of the SNOTEL sites near the Trail show zero inches of snowpack by the first week of June, even though there is usually a lot of snow on the Trail at treeline and above. This is likely due to the location of most of the SNOTEL stations as well as the variable depths due to drifting.

There are, however, two particularly helpful SNOTEL sites at Fremont and Red Mountain passes, which are more representative of the higher elevation areas on the CT. Fremont Pass is centrally located on the CT north of U.S. Highway 50 and Red Mountain Pass is centrally located on the CT south of Highway 50.

The rules of thumb:

• About one week after the Fremont Pass SNOTEL registers zero inches of snowpack, the high points along the north half of the CT (including in Segments 6, 7 and 8) become passable. Around three weeks after the zero snowpack reading, the high points along the Collegiate West (including CW02-CW05) become passable.
• About two weeks after the Red Mountain Pass SNOTEL registers zero inches of snowpack, the high points along the south half of the CT (including Segments 21-27) become passable.

These SNOTEL links show current snow depth at 11 mountain locations (including Fremont and Red Mountain passes) that are relatively near the CT and at similar elevations.

SNOTEL sites relevant to The Colorado Trail

Gallery of Snowpack Remaining in Spring

Gallery of New Snow in Summer