Sunday, January 30, 2011

How Much does a Snowflake Weigh?

 correction added Feb. 15, 2011*
 One snowflake doesn’t weigh very much – but after awhile all those feathery flakes add up. Ten inches of snow covering an acre of land weighs about 226,000 pound. That’s more snow than you’ll shovel … but the next time a thick layer of white stuff piles up, think about the weight of all the snow you have to clear off the sidewalk.

If there’s a layer ten inches deep, and you clear a sidewalk that’s five feet wide and 50 feet long, you might be lifting and tossing as much as 1300 pounds of snow. Shovel your neighbor’s walk and you’ve lifted a ton or more. After a work-out like that, who needs weights?

Someone who measures such things determined that an individual snowflake weighs 0.02* grams. At that weight it would take 50 flakes to make a gram. For comparison, a Hershey’s kiss weighs 4.7 grams – equal to about 235 snowflakes. There are about 95 kisses in a pound. Using the kiss-to-snow crystal calculator that comes to 22,325 snowflakes/pound.
*this would be the heaviest end of the spectrum. Most are much lighter, weighing from 0.001 to 0.003 grams.

In reality, it’s hard to measure the weight of a snowflake. For one thing, each snowfall is different. Some snow is light and fluffy, and some is heavy and wet. That’s due to the water content in the snow, which is related to the temperature high in the clouds where the flakes began forming, and the temperature of the air they fall through.

The only way to really measure the weight of snow is to let it melt, and then weigh the water. Find a container you can use as your snow-measuring scoop – we use 2-cup deli containers (and the lids). Next time snowflakes fall, go outside and collect a bunch of the fresh stuff. Put a lid on the top (so it doesn’t evaporate) and let it melt. Then weigh it.

You can keep track of the type of snowfall and how heavy it is through the rest of the season. Does spring snow weigh more than winter snow?

Another thing you can investigate is whether old snow weighs more than fresh snow. Or snow that’s been compressed under a snowbank.


  1. My students used information from your post to calculate the number of water molecules in a snowflake. Different students chose heaviest, lightes, average weight - his or her choice. We then discussed how many different arrangements those molecules could make! It was a fun mass-mole-molecule chemistry class opener.

  2. You do not have to melt snow to weigh it.
    Describing the range of snowflakes (and the many types) is much more informative than an "average" weight. So your great mass-mole-molecule gives students practice with several calculations.

  3. Letting the snow melting then weighing it only gives you the quantity of water in this volume of snow. How would you proceed to count the number of snowflakes contained in the volume of snow you collected ?