Hail-Green

HAIL Sam K. and Nasser M.  Green Class



Introduction
Hail is made up of many small, frozen water droplets descending from the sky at rates up to 100 miles per hour. Starting off as water droplets, hail makes many journeys into and out of clouds, being carried up by updrafts. Once the hail stones have gotten too big for the updrafts to carry them upwards, they fall to the ground. (1) These solid balls of ice can cause a lot of damage to trees, housing, and crops, which can be extremely costly. 

Dangers When stones made out of solid ice are falling from the sky at speeds up to 100 mph, they can cause a great amount of damage. Although human fatalities are highly unlikely, damage on trees, crops, cars, and buildings is very common. These small stones are able to tear limbs off of trees, uproot crops, and smash through windows and roofs of cars and houses. Repairing all of this damage is extremely costly, taking on average $1 billion from the world every year. (1)

click this link to learn more about the dangers and formation of hail! []

Conditions of Formation Hail is formed in cumulonimbus clouds and can occur in both warm and cold temperatures. (6) Cumulonimbus clouds are the only ones that can produce hail because of the strong upward vertical wind movements, or updrafts, that are exclusively found in these clouds. (6) Hail forms through a repeated process of falling and freezing. It starts as a small frozen water droplet that falls from the upper section of a cumulonimbus cloud. As it descends into lower and warmer altitudes, it makes contact with super cooled water droplets which eventually encase it. (6) As the droplet reaches the bottom, the cumulonimbus’ updraft will carry it back up to the top of the cloud, where it is colder due to lower air pressure. This will cause the surrounding water to freeze onto the ball and begin to fall again. This process repeats until the hail stone has grown to a size that the updraft can no longer lift its weight, or if the cloud’s updraft dies out causing the hailstones to fall. (6) Higher humidity and stronger updrafts can contribute to the size of the hail stones.

For an explanatory video on the formation of hail click here!

[] Historical Examples

On June 22nd, 2003, the largest hailstone to ever be recorded was discovered. This event took place in Nebraska. The hailstone was 18.5 inches in diameter. (2) On September 17th, 1991, the most destructive hailstorm ever took place in Calgary, Canada. For a full 30 minutes, these 10 cm hailstones showered from the sky and cost more than $342 million in property damage. (4)

Safety Staying safe in a hailstorm is relatively basic. A building with a strong roof will provide the best protection. Most hail storms only last six to fifteen minutes, so until the storm is over, stay sheltered near the center of the room and away from all windows. (7) If you are in a car, pull over immediately and lay face down in the back seats with a piece of cloth covering your eyes. (7) The cloth will provide protection from possible window shards. If you or anyone near you is injured, call 911 and report the size of the hailstone, then wait for instructions from the dispatcher until help arrives. (7)

<span style="color: #478cf0; font-family: 'Comic Sans MS',cursive; font-size: 170%;">Sources

1) "Severe Weather." //National Oceanic and Atmospheric Administration//. US Dpt of Commerce or NOABZ. Web. 9 Jan. 2012. <http://www.noaawatch.gov/themes/severe.php>.

2) "Hailstorms." //Severe and Hazardous Weather//. Web. 19 Jan. 2012. <http://severewx.atmos.uiuc.edu/index.19.html>.

3) "Rain+Hail." //Ww2010//. Web. 11 Jan. 2012. <www.ww2010.atmus.vivc.edu//(GH)/guides/mtr/cld/prcp/rnhl.rxml>.//

//4) "Hailstorm Preparation."// Canadian Direct Insurence//. Web. 15 Jan. 2012. <http://www.canadiandirect.com/Home/Safety/Hailstorm.aspx>.//

// 5)"Hail - Severe Weather Awareness." //National Weather Service Eastern Region Headquarters//. Web. 20 Jan. 2012. <http://www.erh.noaa.gov/cae/svrwx/hail.htm>.//

// 6) Allaby, Michael. //Tornadoes- Dangerous Weather//. New York: Facts on File, 2004. Print.//

// 7) "Hail Safety TIPS." //City of Fort Collins Office of Emergency Management//. Web. 15 Jan. 2012. <http://www.fcgov.com/oem/pdf/hail-brochure.pdf>.//

//8) "Hail."// The Weather Chanel//. The Weather Chanel. Web. 11 Jan. 2012. <www.weather.com/encyclopedia/thunder/hail.html>.