Michigan snow: How does snow form and where did it come from?

(Getty Images)

After a few small snow events, we finally have that big snow we’ve been looking forward to all season. More than a foot of snow could fall in Southeast Michigan today and tomorrow.

This doesn’t happen by accident. Several things need to come together to produce a snowfall this large.


Let’s start at the beginning. Available moisture and temperature are necessary factors for snow. In fact, snow formation starts off much the same as rain, beginning as water droplets. 

As the cloud containing water droplets rises into higher, cooler layers of the atmosphere, or as cooler air moves in to lower the temperature, the water droplets freeze into ice and snow crystals form. Snow forms when tiny ice crystals in clouds stick together to become snowflakes. 

The crystal grows by continuing to collect water vapor (water in the form of gas), attaching water droplets to its surface.

Clumping together, one snowflake can contain as many as 100 ice crystals. When the crystals are heavy enough, they fall to the ground.


The size and composition of a snowflake depends on how many ice crystals stick together. This is often determined by air temperature. Precipitation reaches the ground as snow when the surface temperature is at or below 32F. For temperatures warmer than 35 degrees, the snowflake will melt and fall as sleet instead of snow or rain if the temperature is even milder.


Snowflakes that fall through moist air slightly warmer than 32 degrees will melt around the edges and stick together to form big flakes. What we think of as a wet snow. Snowball making snow. Hard to shovel snow.

 (Photo by Creative Touch Imaging Ltd./NurPhoto via Getty Images)

Flakes that fall through cold, dry air become more of a dry, powdery snow. These snowflakes are smaller and don’t stick together, but are great for outdoor sports. The downside is these type of flakes are more likely to drift in windy weather.

Which type of snow would you prefer?

Up next: the beauty of snow