Snow Is in the Air

Can you imagine the snow-smell in the air?

Have you ever heard anyone say "it smells like snow" or "I feel like it's going to snow today"? Are you one of those lucky people who can feel snow in the air? Could you tell last night that we were going to get this beautiful powder today, even without hearing a forecast? How is this possible?

If you ask around, you are sure to find a range of people, old and young, scientist and amateur, who say they get a certain "smell" or "feel" hours before it snows. An online search will turn up dozens of discussions (like this one) with people trying to put words to this snow sense. Words like fresh, crisp, wet, cold, sharp, and clean are used frequently. Others mention smelling "ozone," "metallicness," or "electricity." Some feel "compressed air" or a "muffleness," and some said they can feel it in their bones or sinuses. What exactly is going on?

Some scientists have found that snow does smell! According to this meteorology expert, some of the chemicals found in snow include "nitrogen dioxide, formaldehyde, nitric acid, dimethyl sulphide and sulphate and methanesulphonate," all of which have distinctive odors and could be picked up by a very discerning nose. Maybe these have something to do with the "metallic" smell that some described?

Another explanation for this snow sense is that some people are sensitive to the subtle changes in temperature, pressure and humidity that are happening before a snowfall. Whether or not we end up with snow (and if it looks more like fluff, sleet or hail) depends on how much precipitation is in the air and the temperature - of the atmosphere where the snow forms (up in the clouds), the air through which the snow falls, and whether or not the ground it lands on is frozen. Air must be below freezing in order for precipitation to turn to snow. However, very cold air does not hold moisture very well. Snow usually occurs when the air is actually warming and the humidity is increasing. So we may notice a slight temperature difference or be able to feel a saturation in the air.

Stirring up some fresh fluff!

Fronts are responsible for most changes in weather. These happen when a large mass of cold air and warm air meet, and differences in their density make the air fall (if it's colder) or rise (if it's warmer), changing the pressure to be high or low, respectively. Precipitation usually forms in an upward flow of air. Some astute people might be able to pick up these changes in their joints or sinuses. Or this pressure and humidity change might make the air feel more "muffled" or "compressed."

Do you have a "snow nose," or do you know anyone who can always predict when it's going to snow? What words would you use to describe what you sense? Let us know!

Want to learn more?

• Read these tips and info on weather prediction.
• Try any of these 32 fun snow activities from hands on : as we grow.
• From powder to slush, learn about the water content of different kinds of snow.
• See how animal tracks look in the snow on the UW-Arboretum's Family Walk this Sunday.
• The best way to learn about snow and how to predict it is to get outside - you can train your nose and your gut to pick up on changes in the natural world and test your predictions. Good luck!