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View Full Version : The sky is falling!!! The sky is falling!!!



brainsmile
03-10-2006, 09:55 PM
Oh... nevermind. I looked it up on the internet and I think it's called hail.

Hail is a type of graupel, a form of precipitation, composed of spears or irregular lumps of ice. It occurs when supercooled water droplets (remaining in a liquid state despite being below the freezing point, 0°C/32°F) in a storm cloud aggregates around some solid object, such as a dust particle or an already-forming hailstone. The water then freezes around the object. Depending on the wind patterns within the cloud, the hailstone may continue to circulate for some time, increasing in size. Eventually, the hailstone falls to the ground, when the updraft is no longer strong enough to support its weight.


HailstormHail often forms in strong thunderstorms, often along a cold front, where the layer of air on top is much colder than that on the bottom. The smaller hailstones can travel up and down between the warm and cold layers due to updrafts and gravity. The longer the stones circulate in the cloud, the larger they grow. For the same reason, larger hail can occur in warmer regions of the world due to stronger updrafts. These strong, severe, or even supercell thunderstorms usually occur in summer, and don't require a cold front. Hail clouds are easily identifiable by their green colouration.


After a mild summer hailstorm in Brisbane, Australia — a subtropical regionHail can do serious damage, notably to automobiles, skylights, and glass-roofed structures. Rarely, massive hailstones have been known to cause concussions or fatal head trauma.

Hailstones, while most commonly only a few millimetres in diameter, can sometimes grow to several centimetres or occasionally even bigger. Pea or golfball-size hailstones are not uncommon in severe storms. The image to the right shows an aggregate hailstone with smaller stones visible. The ruler shows the size of this hailstone as approximately 6 cm, almost the size of a tennis ball.


Small hail from a thunderstorm, compared to a U.S. quarter, in San Jose, California.One of the most notorious regions for large hail is northern India and Bangladesh, which have reported more hail related deaths than anywhere else in the world and also some of the largest hailstones ever measured. China is also notorious for killer hailstorms.

Small hail can occur without accompanying thunderstorms, particularly in winter — most notably in temperate and sub-arctic/sub-antarctic regions. Hailstorms in equatorial, tropical and sub-tropical regions almost always occur in the warmest months of the year and are accompanied by thunderstorms. Generally speaking, hail occurs in areas that are either susceptible to thunderstorms or cold weather.

Itsme
03-11-2006, 06:13 AM
When I worked in North Dakota for a year, many years ago, we had hail as large as the size of a baseball. Lots of cars last their windshields that day.

For many years I kept news pictures of the hail on the ground...not sure I could find it now. I'll bet a google image search might come up with somethig though.

Markel
03-11-2006, 08:40 AM
A number of years ago, the town of Oak Park, Illinois, decided to mimic the dubious attempts of other cities to revive their downtowns by closing down the street and making it a mall. (They have since reversed this and re-opened the street.) Anyway, one Saturday they were having an antique car show on the mall. I was there when the weather deteriorated to near-tornado conditions (the sirens were going off). Huge hailstones were falling, and I could see some of the car owners near tears as they watched their 35 layers of lacquer getting pummeled by near-baseball-sized chunks of ice.