Early Season Snowfall In Colorado
Early Season Snowfall: The Good, The Bad, & The Ugly
Early season snowfall in the West brings both excitement for winter sports enthusiasts and warnings of potential hazards, as recent avalanche activity underscores the unpredictable nature of these early snow conditions.
As we welcome the first snowfall in the high country, some areas across the West are already reporting several inches—or even feet—of snow. While many of us are eager to hit the slopes, it’s crucial to remember that early season snow can pose significant dangers in the backcountry, some of which may set us up for instabilities throughout the winter to come.
Recent Avalanche Activity
This October has already seen avalanche activity in Colorado, highlighting the dangers of early season conditions. Our first avalanche was reported in the San Juan Mountains, prompting local officials to issue warnings about unstable conditions and early season snowfall. These incidents serve as a stark reminder of how quickly early season snow can become a hazard.
Photo courtesy of CAIC. Silverton area on Oct 20th, 2024. Near treeline on West facing aspect
People Come from Around the World to Study Colorado’s Continental Snowpack
Colorado’s snowpack is infamous for its cold, dry, and shallow conditions. Early season snow storms may bring a brief flurry of activity, but they’re frequently followed by long stretches of cold, dry weather before the next storm cycle arrives. If this early snow doesn’t melt away, the snow grains can break down into what we refer to as facets, or “sugar snow.” These unbonded, sugary crystals can then create weak layers in our snowpack that persist, meaning, they can stick with us for the duration of our winter season and plague us with instabilities – the root cause of many avalanches.
Photo: Digging into the snow can help us gain valuable information across space and time. Justin Ibarra – Copyright 2023
Depth hoar and faceting
When snow begins to fall in earnest, new layers of snow accumulate on top of these weak, sugary facets which leads to a fragile base layer in the snowpack. This unstable layer can trigger avalanches, potentially impacting the entire snowpack. One key factor to the formation of facets is the large temperature gradient, that is, significant temperature fluctuations within the snowpack. In Colorado, colder fall air combined with warmer ground can create a steep temperature gradient in a shallow snowpack. Mother nature does not like drastic change, and these snow grains will then change shape into angular facets that don’t bond and thus create weak snow. Ideally, we want consistent snowfall early in the season, allowing for a deeper snowpack and a more gradual temperature change which helps prevent the formation of these weak layers near the ground.\
Photo: Justin Ibarra – Copyright 2023
The Role of Sun Exposure
Another important aspect to consider with early season storms is how varying sun exposure affects snow retention. As the fall equinox passes, the sun moves lower in the sky, leading to increased melting on southerly aspects. Extended periods without snow can cause southerly slopes to become nearly bare. In contrast, northerly and shaded slopes tend to remain colder and retain snow, increasing the danger. This is key in understanding the importance of tracking conditions throughout the season, and it starts with these early season snowfall events. Try to record where has the snow melted, and where has the snow persisted. This provides us clues which terrain might hold a more unstable and problematic snowpack.
Photo: Here is a great example of southerly aspects melting out, and northerly and shaded terrain harboring early season snowfall. Justin Ibarra – Copyright 2023
Warning Signs of Early Season Avalanche Danger in Colorado:
Recent snowfall: Large and rapid accumulations may overwhelm weak layers or create instability within the new storm snow.
Wind loading: Wind can transport snow and create new slabs on leeward slopes. Wind, the architect of our snowpack, can move and accumulate snow 3-5x faster than it falls out of the sky. This means with ideal wind speeds, a 6-inch storm can drift over 2 feet in certain areas.
Interface: What is the snow falling on? Again, to assess this factor, it is so important to have an understanding of what the conditions are on any given piece of terrain before each snowfall. In early season we clue into what terrain (aspects, elevations) the snow has melted on, and where in the terrain the early snow has remained. New snow falling on bare ground can provide less of a chance for snowpack instability but an increased chance of trauma of rocks, trees, etc. along with broken gear and core shots. New snow falling onto early season snow and weak layers will increase the danger of avalanches.
Conditions that Mitigate Against Early Avalanches
1. No significant early season snow until November, followed by major snow events, with little wind.
2. Early season snow that melts away completely before significant snowfall accumulates.
Mitigation Strategies
To mitigate the risks associated with early season snow and avalanche conditions, consider the following strategies:
1. Get Education and Training: Attend clinics, read books, and take an avalanche safety course to better understand snowpack dynamics and to recognize hazards.
2. Gear Up: Always carry essential avalanche safety gear, including a beacon, shovel, and probe, even when it seems too early to be needed. Ensure your gear is in good condition.
3. Check Conditions: Before heading out, consult the Colorado Avalanche Information Center (CAIC) for current avalanche forecasts and conditions.
4. Choose your partners wisely: Travel with others and maintain open communication. It is crucial that every member of your group is a contributing member and speaks up with what they see, feel, and hear.
5. Choose Your Terrain Wisely: Stick to low-angle slopes in unstable conditions. Avoid terrain traps, such as gullies, trees, and cliffs that can amplify the effects of an avalanche. Terrain is the main tool we use to manage risk when dealing with an unstable snowpack.
6. Practice with your safety gear and your backcountry companions. This is a great time of year to practice rescue scenarios!
7. Tune up and repair your ski or splitboard bindings, edges, boots, and skins. Go through and replenish your first aid and repair kits.
