Nature Notes: Snow Science
By Anna Foster
If you’re anything like me, you might have groaned when you saw the first dusting of snow two weeks ago. The winter season brings opportunities for adventuring on snowshoes, cross country skis, snowmobiles, and ice skates… but it also means getting up 30 minutes earlier to shovel off your car. However, annoying it may be to pull on your extra layers and winter boots at 6:30am, you can’t deny that snow in Door County transforms the landscape into a beautiful winter wonderland.
When I was little, I’d look forward to riding our horses in the snowy fields, daring to sled down Hill 17, and seeing if our minivan would slide all the way down the hill in Sister Bay (I don’t think my mother thinks of that last memory as fondly as I used to). Snow and ice have always been a part of our lives here in northern Wisconsin, whether we like it or not. So, what is snow, how does it form, and how does it impact our landscape?
Lesson #1: Don’t Eat Snow!
Our lessons for Forest Days at Gibraltar change throughout the years as students explore the forest habitat and learn more about their ecosystem. However, there’s one lesson I’m sure to show students every year. Inevitably, during our first snowy hike out into the forest, a student picks up some snow and puts it in their mouth. Snow cones may be fun to eat, but their ingredients aren’t as appetizing as one might think.
Snowflakes are not frozen raindrops. They form when water vapor in the atmosphere attaches to dust or pollen particles, skips the liquid phase, and condenses into ice crystals. These ice crystals will stick to one another and eventually become heavy enough to fall to the ground.
You’ve probably heard the phrase “don’t eat the yellow snow.” Well, the saying really should be “Don’t eat the snow, period.” When I pass around a jar of melted snow to all the students in our Forest Day class, they can see all the dust particles around which snowflakes form. The water inside the jar is clearly dirty, with some larger dust particles floating around inside. This usually stops students from putting snow into their mouths during Forest Days and helps them conceptualize how snow forms in the atmosphere.
Lesson #2: Warmer Conditions = Heavier Snow
The moisture content in the atmosphere determines the density, “wetness,” and what type of crystal formation will fall to the ground. If the air is warm (around 32 degrees Fahrenheit), the moisture content in the atmosphere will be greater, and the snow crystals falling to the ground will be heavy and wet. The temperature in the atmosphere also determines the type of snowflake that will form. Water crystalizes differently at different temperatures. For example, long crystal arms form at 23 degrees Fahrenheit, but at 5 degrees Fahrenheit, plate like crystals will form. However, a snowflake always forms with six branches.
The weather on the ground also determines the characteristics of snow. If temperatures remain below freezing, snowflakes will change shape once on the ground due to wind and temperature changes. Lighter snow tends to drift more easily, causing larger piles of snow in places with natural barriers and sometimes covering roadways.
How much water is in snow? Even though snowflakes are made of ice crystals, there’s a lot of air in between the ice crystals in a snowflake. Only about 4-10% of snow is water, depending on the weather conditions at the time of snowfall. So, ten inches of snow is equal to or greater than one inch of water. Although this may not seem like a large amount of water, the melting of the snow in the spring causes water levels to rise and can even flood the lowlands of the peninsula. This snow melt is important for spring ephemerals and other organisms that emerge in early spring.
Lesson #3: Snow Can Be Dangerous
Over the course of a winter, the layers of snow that accumulate on the ground form a “snowpack.” Snowpacks show us the types of snow grains that have fallen on the ground over time, revealing what weather and atmospheric conditions existed at the time of a particular snowfall. Wind and water can also impact snow formation. For example, snow drifts often form along the shore in Baileys Harbor and along the Lake Michigan shoreline. These can be extremely dangerous to walk on because the appearance of the snow drifts is deceiving. Many snow drifts can have hollow ice shelves underneath. Unfortunately, many people have walked out onto snow drifts where the ice underneath does not support their weight.
Cornices, overhanging shelves of snow, can also form on the faces of mountains, cliffs, and bluffs. Always use extreme caution when hiking on snow formations. Stay off of snow and ice shelves on the edges of water bodies and stay far away from cliff or bluff faces when hiking in snow. In addition, always check the weather before heading outside in the winter. Dressing properly for snow and cold temperatures can save your life.
Lesson #4: Celebrate the Season!
Living in the snow is no joke. We all take extra precautions in the winter to reduce our exposure to cold weather, reduce the risk of traveling in snow, and even to protect our houses from the elements. However, snow also allows us to experience a whole new landscape during the winter months. You can read more about how animals adapt to snow and the subnivean layer in Jackie Rath’s blog from last year here.
This year, we have many opportunities to experience the winter season at The Ridges! First, we have our most magical event of the year coming up on Saturday, December 10th. Join us in celebrating Natural Christmas from 3:00pm-6:00pm. This year’s theme is Winter Wonderland, where we’ll be celebrating snow and all the critters that are out and about in the sanctuary during this time of year. Our Kaye Cabin will be decorated to the nines, with music, cookies, and hot chocolate. We’ll also have a campfire, a craft cabin, Range Light tours, guided hikes, luminary-lit boardwalks, and wreath making in our workshop! Natural Christmas is a free event and fun for the whole family. The Wreath Making workshop is $25, including materials for the wreaths.
If you’re visiting between the holidays, we will have our annual Luminary Walks between Christmas and New Year’s. Join us from 5:00pm-7:00pm to experience the softly lit boardwalks and peaceful sanctuary surroundings. The $5 trail fee applies.
Lastly, we’ll be starting our Winter Guided Hikes in January! Come learn more about snow and the winter landscape of the Sanctuary on Friday afternoons at 1:30pm and Saturdays at 10:30am and 1:30pm. If the weather allows, we will experience the Sanctuary while snowshoeing. Snowshoes are also available to rent from the Cook-Fuller Nature Center any time during the winter if there is enough snow on the ground.
We’ll see you out on the trails!