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?”

We put together a blog post with some great information on this topic. The info from that blog also occupies the upper section of this page. It’s such a common topic, that we’ve decided to also retain all of our previous information on this topic. So, this page is long and packed deep (see what we did there) with data. We hope you find it all useful in your quest to predict the conditions of your hike!

Updated Information

We hear it every year, from the conclusion of one hiking season to the beginning of the next. What is the snowpack like on the Colorado Trail? We hear this from people planning a thru hike for the next season, and from section hikers looking to tick off sections in the wintertime. Snow levels are notoriously difficult to predict, but there are many tools available to help answer the question.

Starting a thru hike on or after July 1 has, in most years, worked well for travelers starting in Denver. Because it will take several days to reach the high elevation passes, particularly those in Segments 6, 7 and 8, this start date allows additional days for the remaining snowpack to melt. The Collegiate West segments are, historically, the last to melt out. They also take some time to get to, if you begin at Waterton Canyon.

If you are a user of OnX, Gaia, CalTopo, or most other GPS applications (available on your phone or desktop) you likely have access to several excellent current conditions map layers, including snow depth. These advanced layers are usually only available to “premium” subscriptions, meaning you may have to pay a small monthly fee to access them. Much of the data these applications use is accessible for free to the public with the main advantage of using the app is that you can upload the CT centerline and view it against whatever data layer you desire.

Fortunately, there are also many useful and free resources to help determine current snow conditions on or along the CT. First, is SNOTEL or Snow Telemetry. The SNOTEL network is composed of over 900 automated data collection sites located in remote, high-elevation mountain watersheds in the western U.S. They are used to monitor snowpack, precipitation, temperature, and other climatic conditions. This interactive map from the Natural Resources Conservation Service provides a wealth of information from SNOTEL sites with a user friendly interface. You can view things like the Snow Water Equivalent at each SNOTEL site, and on a basin wide map. There is a ton of information here, so spend some time exploring the different options to find the data you find most useful. You’ll probably want to review this glossary of climate terms as you explore this interface, best viewed on a desktop.

Another useful and user-friendly site is hosted by the Community Collaborative Rain, Hail, and Snow Network or CoCoRaHS. Yeah, that’s a mouthful. Their interactive map has some useful climate data and is also best viewed on a desktop. The data is controlled with the GUIs on the top right of the screen and can be made very specific to what you are looking for.

One more worth noting is the Snow Forecast that claims to be “predicting sick days since 1998.” If nothing else, we appreciate the humor. But, there is much more to this site. Note the map layers are controlled on the left hand side of this site. The most frustrating lack of features here, is the lack of a legend to tell you what the map is showing.

Map overlays are great, but still don’t provide the site-specific details we often crave. Thankfully, the proliferation of web cams can help us in this effort. We’ve compiled a list of webcams along the CT for some hyper local condition observations. As of December 2023, these links are viable. If you know of any other reliable web cams in the vicinity of the CT, let us know and we will add them to the list here.

Camera closest to Waterton Canyon, southbound starting point.
Camera closest to Segment 6 TH on Highway 285.
Camera closest to Segment 7 TH, Gold Hill, Breckenridge.
Camera closest to Segment 8 TH, Wheeler Flats, Copper Mountain.
Camera closest Segment 9 TH, Tennessee Pass, Ski Cooper.
Camera closest to Twin Lakes, Granite.
Cameras closest to Segment 14, Mt. Princeton Hot Springs.
Cameras in Buena Vista, eastern slope of the Sawatch mountains.
Camera near the southern junction of Collegiate East and West, Monarch Crest.
Cameras at Monarch Mountain ski resort, CW05.
Camera closest to Segment 18, Cochetopa Hills.
Camera closest to Segment 22, Spring Creek Pass.
Camera closest to Segment 25, Molas Lake, Silverton.
Camera closest to Junction Creek, CT southbound terminus.

Predictions for average melt off dates are as follows and highly dependent on winter snow accumulation, elevation (between 5,522 and 13,271), and aspect. If we have a mild winter, take a week or two off these estimates. Conversely, if we have a wet winter add some time on.

Segment 1, 2, and 3, early May
Segment 4, mid-June
Segment 5, late May
Segments 6, 7, and 8, early July
Segment 9, late June
Segment 10, mid-June
Segment 11 late May
Segments 12, and 13 mid-June
Segment 14 early June
Segment 15 early July
Segments 16, 17 late June
Segment 18 late May
Segment 19 late May (creek ford possibly fast & deep until, say, mid-June)
Segments 20, 21 late June
Segments 22, 23, 24, 25, 26, 27, and 28 early July
Segment CW01 early July
Segment CW02 mid-July
Segments CW03, CW04, CW05 early July

Preparation in all aspects of your trip is important to your enjoyment and success on the CT. We hope this blog, as well as the many others we have compiled, helps in this effort. Good luck, and happy trails!

Previously Compiled Information

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 passable norm reports on our blog 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, find links to trail groups on our trail alerts page.
Another resources is SNOTEL, information and links to sensor reports, below.

SNOTEL Snowpack & Climate Sensors

SNOTEL (short for snow telemetry), is 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.

SNOTEL sites relevant to The Colorado Trail

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.

Nearest CT Location	Snotel Site	Site Elevation	Approx. miles from CT	Snow Depth Last 7 Days
Segment 6 Georgia Pass	Michigan Creek	10,600	1.5	Snow Depth Michigan Creek
Segment 8 Copper Mountain	Copper Mountain	10,300	0.3	Snow Depth Copper Mountain
Segment 8 Kokomo Pass	Fremont Pass	11,400	3.7	Snow Depth Fremont Pass
Segment 15 Fooses Crk/ Marshall	Porphyry Creek	10,760	3.3	Snow Depth Porphyry Creek
Segment 17 Sargents Mesa	Sargents Mesa	11,530	0.3	Snow Depth Sargents Mesa
Segment 18 Cochetopa Pass	Cochetopa Pass	10,020	0.8	Snow Depth Cochetopa Pass
Segment 22 Jarosa Mesa	Slumgullion	11,440	3.5	Snow Depth Slumgullion
Continental Divide atop Elk Creek	Beartown	11,600	0.6	Snow Depth Beartown
Segment 24/25 Molas Pass	Molas Lake	10,500	0.3	Snow Depth Molas Lake
Segment 25 Rolling Pass	Red Mountain Pass	11,200	9.3	Snow Depth Red Mountain Pass
Segment 27/28 Kennebec Pass	Columbus Basin	10,785	0.9	Snow Depth Columbus Basin