Tuesday, February 13, 2007

Snow is precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes

So it's sleeting outside (so I thought) and come to find out that it really is sleet. What the heck is the difference between snow and sleet, and just WHY? So, I did what any common sensed person would do and looked it up. I thought I'd share because I'd like to think that I'm not the only one who doesn't know. If I am, feel free to have a giggle to yourself on my account. I am so taken by the whole snow thing. Who would have known? (Take a look out into our back yard and you'll see why I'm so taken - even with a tiny bit of snow it sure is beautiful!)

  • Snow: Falling ice composed of crystals in complex hexagonal forms. Snow forms mainly when water vapor turns directly to ice without going through the liquid stage, a process called deposition.
  • Snowflakes: Aggregations of snow crystals.
  • Snow flurries: Light showers of snow that do not cover large areas and do not fall steadily for long periods of time.
  • Snow grains: Very small snow crystals. The ice equivalent of drizzle.
  • Snow pellets: White, opaque ice particles that form as ice crystals fall through cloud droplets that are below freezing but still liquid (supercooled). The cloud droplets freeze to the crystals forming a lumpy mass. Scientists call snow pellets "graupel." Such pellets falling from thunderstorms are often called "soft hail."
  • Sleet: Drops of rain or drizzle that freeze into ice as they fall. They are usually smaller than 0.30 inch in diameter. Official weather observations list sleet as "ice pellets." In some parts of the country "sleet" refers to a mixture of ice pellets and freezing rain.
  • Freezing rain or drizzle: Falling rain or drizzle that cools below 32°F, but does not turn to ice in the air. The water is "supercooled." When the drops hit anything they instantly turn into ice.
  • Ice storm: A storm with large amounts of freezing rain that coats trees, power lines and roadways with ice. Often the ice is heavy enough to pull down trees and power lines.
  • Hail: Falling ice in roughly round shapes at least 0.20 inch in diameter. Hail comes from thunderstorms and is larger than sleet. Hailstones form when upward moving air -- updrafts -- in a thunderstorm keep pieces of graupel from falling. Drops of supercooled water hit and freeze to the graupel, causing it to grow. When the balls of ice become too heavy for the updrafts to continue supporting them, they fall as hailstones. Sleet, in contrast, consists of raindrops that freeze on the way down.
And here I thought a deposition was a legal thing...who knew!

Oh - thanks to USA Today for these great definitions! There's more here if you want to know about rain, storms, etc.

2 comments:

Anonymous said...

I'm so glad that you are back! I've missed your interesting blog. Sorry that I've been MIA too. I'll have to sit down and write an e-mail soon and update you on everything going on. This weekend is the scrap retreat, though, so it won't be before then! We will miss you!

Becky :)

Krissy said...

Yeah!! SNOW!! I am jealous!