Wednesday, April 20, 2011

frozen precipitation

Snow in April makes me cranky.

Snow in April during Daniel's spring break for which I had planned all manner of outside activities including, but not limited to: playing outside, going on picnics, visiting the zoo, playing outside, working in the garden, starting a new vegetable plot in the front yard, and did I mention playing outside? makes me extra cranky.

But we didn't just get snow. We got everything. I complained about this in passing to my parents (on the phone, or in an email, or both - I don't remember now) and I got an email from my dad with an entire glossary of terms describing frozen precipitation (if you know my dad, this shouldn't surprise you):

From "Glossary of Weather and Climate":

frozen precipitation--Any form of precipitation that reaches the ground in frozen form (e.g., snow, snow pellets, snow grains, ice crystals, ice pellets, hail).

snow pellets (formerly called soft hail or graupel)--A type of frozen precipitation consisting of soft spherical (or sometimes conical) particles of opaque, white ice having diameters of 2-5 millimeters. They often break up when striking a hard surface and are distinguished from snow grains in being softer and larger.

snow grains (also known as granular snow)--A form of frozen precipitation consisting of white, opaque particles of ice that are flat or elongated and have diameters of less then 1 millimeter; the solid equivalent of drizzle.

ice pellets (also called sleet)--A type of frozen precipitation consisting of transparent or translucent pellets of ice 5 millimeters or less in diameter. They may be spherical, irregular, or (rarely) conical in shaped. Ice pellets usually bounce when hitting hard ground and make a sound upon impact. There are two types of ice pellets; (a) frozen rain, drizzle, or largely melted then refrozen snowflakes; (b) snow pellets encased in a thin layer of ice.

sleet (also known as ice pellets)--In the United States, frozen raindrops that bounce on impact with the ground or other objects. Elsewhere, may refer to a mix of rain and snow, a mix of rain and hail, or melting snow

Every kind of ice that can fall from the sky did so yesterday except hail, which is defined as follows: hail--A type of frozen precipitation in the form of balls or irregular lumps of ice, usually consisting of concentric layers of ice. Hailstones come in a variety of sizes and shapes. Hail is always produced by convective clouds, nearly always cumulonimbus. Thunderstorms that are characterized by strong updrafts, an abundant supply of supercooled water droplets, and great vertical development are favorable to hail formation. Large hail, with diameter of 3/4 inch or greater, is a criterion for a severe thunderstorm. (Not: this criterion was changed to 1" just a couple years ago.)

Daniel and Anya and I had the particular privilege of experiencing firsthand just how uncomfortable and painful it is to walk outside during a heavy downfall of graupel (aka "snow pellets" as noted above). We were trying to exit a large home improvement store with a newly purchased ceiling fan (that we thought would be installed today, hence the hurry to buy one, but then it turned out the electrician was running on a tight schedule and will get to it in a few weeks), but after about three seconds of being pummeled with bits of ice that felt like someone fired a shotgun from the heavens, we turned right around and decided to wait it out inside the store. I won't tell you which of my children thought it would be a good idea to pick up one of the ice pellets from the filthy floor and lick it.

It's been kind of a long week, is all I'm saying.

1 comment:

Jessi said...

Yuck! Hope it warms up a bit for you. We're going to drown in rain this weekend. :(