Snow storms, according to the Natural Disasters Association, occur when air and ground temperatures fall below freezing. Each year, roughly ten snowstorms hit North America and Canada, affecting approximately 2.5 million people. The impact of these storms is often compounded by high winds which can cause additional damage or loss of life.
Using data from the National Weather Service and other sources, we can calculate the number of people affected by snow storms. First, we need to know the total population living in areas likely to be impacted by snow storms. According to the 2010 U.S. Census, the total population living in regions likely to be affected by snow storms was estimated to be between 36 and 40 million people.
Next, we need to know how much snow falls during typical snow storms. The average snow depth over time has been found to be about six feet. However, this number varies depending on the region of the country being considered. Deep snow packs the ground down, making it difficult for drivers to navigate. As a result, more people die in snow storms than might otherwise be expected.
Finally, we need to know how long after the start of the storm that most deaths occur.
Why do ice storms occur so frequently in Ottawa?
Snow falls when the atmosphere is "cold" all the way from the clouds to the ground. Precipitation begins as snow in the cold layer at the top, melts as it falls through the warm layer, then refreezes when it falls through the cold layer at the surface. The amount of precipitation depends on how much water is in the form of ice particles in each layer.
Freezing rain happens when large amounts of moisture in the form of ice crystals are blown by wind into a region where the temperature is below 32 degrees F. The ice crystals can be as small as dust. When it freezes, ice becomes transparent so we can see what's under it.
As freezing rain falls, it will begin to thaw out at the surface. The water molecules in the ice are still frozen solid at that depth but as they reach the warmer surface, they will start to melt, increasing the volume and raising the temperature of the liquid. This process continues until all the ice has melted away. When the last bit of ice has melted, only liquid remains.
The heat from the sun melting the ice crystals in freezing rain can also cause damage to trees and other plants. The water from the melting ice flows down their branches and can kill the tips of young growth or damaged parts of the tree.
Freezing rain is dangerous for people too.
Winter storms create a higher risk of car accidents, hypothermia, frostbite, carbon monoxide poisoning, and heart attacks from overexertion. Winter storms, including blizzards, can bring extreme cold, freezing rain, snow, ice and high winds. Last a few hours or several days. These storms can be very dangerous for young children, the elderly, and those who are sick.
The most serious danger from winter storms is damage to people who don't take weather warnings seriously. Even if you can see past the snow, ice, and wind, you need to know what dangers your area may face before you go out in it.
Here are some other things to keep in mind:
Blizzards and similar severe weather events can cause power outages which can lead to carbon monoxide leaks. Make sure you have enough heat in your home to stay safe during cold weather conditions.
Fog is often accompanied by slick roads that could cause traffic accidents. Be aware of changing conditions when driving.
Heavy rains can cause flooding and erosion damage to roads and sidewalks. Plan ahead to make sure you're not put in a position to need to use these services.
If you live in an area likely to experience coastal flooding or other natural disasters such as earthquakes, find out how much danger you're in and what actions should be taken if one happens.
Every year, somewhere on Earth, around 1015 (one quadrillion) cubic feet of snow fall, with each cubic foot comprising a few billion (109) individual snowflakes. That's about six feet of new snow per second! The number of snowflakes in a snowflake layer is called its "density." The average human hair is about 75 microns wide; the thickest known natural fiber is cotton leaf lint, which can be up to 300 microns wide. Thus, the average snowflake is about 750 microns across.
The density of the cloud base above any given region influences how much water will vaporize when it melts in spring and melt again in winter. More dense clouds will hold more water than thin clouds will, so more liquid will vaporize. More vaporized liquid will enter the air as rain or snow depending on the temperature. The amount of precipitation that results is called the storm's potential energy budget. A strong storm can have a positive energy balance and produce more snow than normal while a weak one can have a negative balance and produce less snow than normal.
The density of a cloud also affects how far it can travel before it melts. Thin clouds don't last long enough to cover large distances before melting away, but heavy clouds can carry moisture hundreds of miles from their source region.