FreezingRainTan

= ﻿ bbbbbbbbbbbbbbbbbbbbb Freezing Rain = Betsy W. & Ellen K. Tan Class

Introduction
Freezing rain is one of the many severe weather conditions people experience here on Earth. Freezing rain is when supercooled droplets of water freeze once they impact Earth's surface (3). It can create ice storms, power outages, transportation difficulties, and create dangerous glaze (3). Freezing rain can occur in many places, but is commonly found in lower elevations where naturally cold and dense air settles (4).

Dangers
Freezing rain can hurt both people and property, often times severely, because when it collects as ice on smooth surfaces, it is nearly invisible, and therefore difficult to identify. (1) It is the cause of many car accidents due to icy roads, as well as slips that result in broken necks, hips, ankles or wrists. (5) These fractures are greatly increased by freezing rain. (5) It is common to fall down front steps or on sidewalks and loading docks. (5) For example, paramedic Martin Lesperance took care of a man who slipped down three steps, broke his neck and was paralyzed from the neck down. (5) Furthermore, when freezing rain hits telephone wires and poles, they are coated with a layer of ice. (2) This ice often weighs these objects down, cutting off power and communication. (2) It is common to lose heat during a freezing rain storm, which can eventually lead to hypothermia. (11) For instance, in 1921 during a severe storm the ice between two telephone poles was estimated to weigh over four tons. (2)



Conditions of Formation
S imply, freezing rain occurs when rain that has become supercooled freezes when it hits a solid on Earth's surface. (2) Pure water suspended in the air doesn't freeze at 0 degrees Celsius, but rather at -40 degrees Celsius. (6) Water in liquid form below 0 degrees Celsius is supercooled. (6) This water will freeze once it touches a solid. (6) In order for freezing rain to occur, the atmosphere must have a warmer layer, then a shallow layer of cold air (a subfreezing layer). (1) When air reaches its dew point as it rises and cools adiabatically, it condenses to form clouds. Cold clouds create precipitation by the Bergeron process. (6) This is when saturated air is supersaturated in terms of ice. (6) So excess water vapor becomes ice, which lowers the relative humidity close to the nearby droplets. (6) As water drops evaporate and ice crystals continue to grow, crystals are created that are big enough to fall. (6) These crystals fall and hit cloud drops which cause them to freeze, creating snowflakes (larger ice crystals). (6) This is the start to the formation of freezing rain. If freezing rain is to form, this snow continues to fall until it reaches a warmer layer of the atmosphere. (1,2) This warm layer is about 2,000 to 3,000 feet above a subfreezing layer of air overlying the ground. (1,2) In the warm layer the snow melts. Subsequently the rain enters the colder layer above ground where the drops supercool and fall as rain that freezes when it hits a solid. (2) Therefore, in order for freezing rain to occur, a warm layer must overlie a subfreezing layer of air. (1,2) If these conditions aren't exact, freezing rain will not form. (1) For instance, if the subfreezing layer is too deep, the rain will freeze and the form of precipitation will be ice pellets or sleet. (1) But if this layer is too thin, regular rain will fall. (1) Freezing rain is usually found in a thin band on the cold air side of a warm front, because air temperatures near Earth's surface there are at or below freezing. (2) The warm air rises, cools adiabatically and condenses, creating a band of freezing rain less than 50 km wide ahead of the warm front. (2) Therefore, freezing rain is common during mid-latitude cyclones or stationary fronts. (2) It is heaviest along a warm front, but can also form along a cold front when southerly winds push warm, moist air over this front. (2) In stationary fronts, light southwesterly winds push warm moist air over the cold air north of this front, producing a band of freezing rain on the cold side of the frontal boundary. (2)

Historical Examples
 Freezing Rain storms have damaged cities and towns all over the world, but one particular storm in Canada, 1988 was said to be the worst case of freezing rain in Canada's history. (7) This claim is based on the amount of ice accumulated, the duration of the storm, and the great amount of the population affected. (7) This storm affected Ontario, Southern Quebec, and Southern New Grunswick for 6 full days, starting on January 5th. (7,11) It covered the whole surface with glaze. (7) Many trees fell, and more continued to break and fall for the entire winter.(11). People were affected too-- 3 million were without electricity and heat, 100,000 retreated to shelters, 945 were injured, and 25 were killed mostly from hypothermia (7,11). Canada's crops were also affected, in particular milk processing plants and maple syrup producers (11). The sugar bush used by Quebec maple syrup was destroyed-- estimating 30-40 years for it to return to its original state. (11) In milk processing plants, an estimated 10 liters of milk had to be dumped out. (11) Lastly, this storm was very costly: $5,410,184,000 was the estimated total. (11)

Safety
In case freezing rain occurs, it is important to learn safety tips to help protect one's self and one's property. If people hear a forecast predicting freezing rain they should travel only if it is absolutely necessary, and allot extra time for delays. (5) If one is driving, that person should be sure to wait for sanding trucks to pass and take extreme caution. (5) People should test the surface of the road by using their breaks gently in order to get familiar with the severity and texture of the ice. (5) If one is driving and nears a car accident, he or she should park in a safe location and turn on his or her emergency flashers. (5) One should not offer help until it is safe to do so. (5) If people are not planning on traveling during freezing rain, they should be sure to have candles, batteries, flashlights etc. ready in case power loss occurs. (1) If people live in the Midwest this is especially important, as this region receives many devastating freezing rain storms. (1) In conditions when freezing rain might occur, it is important to pay attention to weather warnings on the news so that one can prepare. (1)

Links
To see firsthand the destruction caused by freezing rain and its effect on people, watch the following video: Freezing Rain, Flooded Streets and Falling Trees

To learn about an invention used as a sensor to detect freezing rain, look at the following webpage: __Researches Researches Researches__ Comes to ASOS

Sources
(1) Oblack, Rachelle. "Freezing Rain - What Is Freezing Rain?" About.com: Weather.  The New York Times Company, 2010. Web. 17 Nov. 2010.  (2) Wilhelmson, Bob, and Mohan Ramamurthy. "Freezing Rain." WW2010 University of <span style="font-family: 'Times New Roman',Times,serif;"> Illinois. Ed. Steven E. Hall. University of Illinois, 2010. Web. 17 <span style="font-family: 'Times New Roman',Times,serif;"> Nov. 2010. <http://ww2010.atmos.uiuc.edu/(GH)/home.rxml>.

<span style="font-family: 'Times New Roman',Times,serif;">(3) <span style="color: #0000ee; font-family: 'Times New Roman',Times,serif;">__Researches__, Team of. "Wise geek: What is Freezing Rain?". Wise Geek. 20 November 2010 <http://www.wisegeek.com>.

<span style="font-family: 'Times New Roman',Times,serif;">(4) <span style="font-family: arial,helvetica,sans-serif;">The Weaher Channel Interactive. "Winter Storm". The Weaher Channel Interactive. 20 November 2010 [].

<span style="font-family: 'Times New Roman',Times,serif;">(5) Lesperance, Martin. "Freezing Rain." Safety Health. Safety Health Publishing <span style="font-family: 'Times New Roman',Times,serif;"> Inc., 1997. Web. 23 Nov. 2010. <http://www.safete.com/safetyarticles/ <span style="font-family: 'Times New Roman',Times,serif;"> weather/freezingrain.htm>.

<span style="font-family: 'Times New Roman',Times,serif;">(6) Edward J. Tarbuck and Frederick K. Lutgens. __Earth Science__. Pearson Prentice Hall, 2009.

<span style="font-family: 'Times New Roman',Times,serif;">(7) Bob, Walsh, John and Charlevoly, Danna. "Severe And Hazardous Weather". Kendal/Hunt Publishing [Date unavailable]. 19 November 2010 <http://severewx.atmos.uiuc.edu>

(8) //CTV.// CTV Globe Media, 2010. Web. 27 November 2010. [].

(9) Angel, Jim. "How Freezing Rain Forms." Illinois State Water Survey, 2009. 28 Nov. 2010 []

(10) Lbg1. //Death by 1000 papercuts//. 29 Jan. 2009. 29 Nov. 2010 [children-for-bread-and-coal/|http://deathby1000papercuts.com/​2009/​01/​deadly-blizzards-and-ice-storms-americans-lose-power-while-afghans-sell-their- children-for-bread-and-coal/].

(11) Monroe, Susan. //Canadian Ice Storm in 1998//. 29 Nov. 2010. 29 Nov. 2010 <http://canadaonline.about.com/​cs/​weather/​ p/icestorm.htm>.

(12) //Culture / In the News//. 5 Feb. 2010. Correctional Service Canada. 29 Nov. 2010 <http://www.csc-scc.gc.ca/​hist/​1980/​culture3-eng.shtml>.