![Ice Storm by NOAA](https://upload.wikimedia.org/wikipedia/commons/3/3f/Ice_Storm_by_NOAA.jpg)
An ice storm, also known as a glaze event or a silver storm is a type of
winter storm
A winter storm is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, mixed snow and rain, or freezing rain. In temperate continental climates, these storms are not necessar ...
characterized by
freezing rain
Freezing rain is rain maintained at temperatures below freezing by the ambient air mass that causes freezing on contact with surfaces. Unlike a mixture of rain and snow or ice pellets, freezing rain is made entirely of liquid droplets. The raind ...
. The
U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least of
ice
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaq ...
on exposed surfaces.
They are generally not violent storms but instead are commonly perceived as gentle rains occurring at temperatures just below freezing.
Formation
![Precipitation by type](https://upload.wikimedia.org/wikipedia/commons/c/c1/Precipitation_by_type.png)
The formation of ice begins with a layer of above-freezing air above a layer of sub-freezing temperatures closer to the surface. Frozen
precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...
melts to
rain
Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...
while falling into the warm air layer, and then begins to refreeze in the cold layer below. If the precipitate refreezes while still in the air, it will land on the ground as
sleet. Alternatively, the liquid droplets can continue to fall without freezing, passing through the cold air just above the surface. This thin layer of air then cools the rain to a temperature below freezing (). However, the drops themselves do not freeze, a phenomenon called
supercooling
Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its melting point without it becoming a solid. It achieves this in the absence of a seed crystal or nucleus around which a crystal ...
(or forming "
supercooled drops"). When the supercooled drops strike ground or anything else below (e.g. power lines, tree branches, aircraft), a layer of ice accumulates as the cold water drips off, forming a slowly thickening film of ice, hence freezing rain.
While meteorologists can predict when and where an ice storm will occur, some storms still occur with little or no warning.
In the United States, most ice storms occur in the
northeastern region, but damaging storms have occurred farther south; an ice storm in February 1994 resulted in tremendous ice accumulation as far south as Mississippi, and caused reported damage in nine states.
Effect
![A street in Elora, Ontario, after an ice storm, early 1900s](https://upload.wikimedia.org/wikipedia/commons/1/15/A_street_in_Elora%2C_Ontario%2C_after_an_ice_storm%2C_early_1900s.jpg)
The freezing rain from an ice storm covers everything with heavy, smooth
glaze ice
Glaze or glaze ice, also called glazed frost, is a smooth, transparent and homogeneous ice coating occurring when freezing rain or drizzle hits a surface. It is similar in appearance to clear ice, which forms from supercooled water droplets. It ...
.
In addition to hazardous driving or walking conditions, branches or even whole trees may break from the weight of ice. Falling branches can block roads, tear down power and telephone lines, and cause other damage. Even without falling trees and tree branches, the weight of the ice itself can easily snap power lines and also break and bring down power/utility poles; even
electricity pylon
A transmission tower, also known as an electricity pylon or simply a pylon in British English and as a hydro tower in Canadian English, is a tall structure, usually a steel lattice tower, used to support an overhead power line.
In electrical ...
s with steel frames. This can leave people without power for anywhere from several days to a month. According to most
meteorologists
A meteorologist is a scientist who studies and works in the field of meteorology aiming to understand or predict Earth's atmospheric phenomena including the weather. Those who study meteorological phenomena are meteorologists in research, while t ...
, just of ice accumulation can add about of weight per line span. Damage from ice storms is easily capable of shutting down entire metropolitan areas.
Additionally, the loss of power during ice storms has indirectly caused numerous illnesses and deaths due to unintentional
carbon monoxide (CO) poisoning. At lower levels, CO poisoning causes symptoms such as
nausea
Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...
,
dizziness
Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness.
Dizziness is a common medical c ...
,
fatigue
Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
, and
headache
Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches.
Headaches can occur as a result ...
, but high levels can cause
unconsciousness
Unconsciousness is a state in which a living individual exhibits a complete, or near-complete, inability to maintain an consciousness, awareness of self and environment or to respond to any human or environmental Stimulus (physiology), stimulus. ...
,
heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
, and death.
The relatively high incidence of CO poisoning during ice storms occurs due to the use of alternative methods of heating and cooking during prolonged power outages, common after severe ice storms.
Gas generators, charcoal and
propane
Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used a ...
barbecues, and
kerosene heater
A kerosene heater, also known as a paraffin heater, is typically a portable, unvented, kerosene-fueled, space (i.e., convectional) heating device. In Japan and other countries, they are a primary source of home heat. In the United States and ...
s contribute to CO poisoning when they operate in confined locations.
CO is produced when appliances burn fuel without enough oxygen present,
such as basements and other indoor locations.
Loss of electricity during ice storms can indirectly lead to
hypothermia
Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe h ...
and result in death. It can also lead to ruptured pipes due to water freezing inside the pipes.
Gallery
File:Trees with Ice.JPG, A tree covered in ice
File:Frozen pinecone.JPG, Detail of a pinecone
A conifer cone (in formal botanical usage: strobilus, plural strobili) is a seed-bearing organ on gymnosperm plants. It is usually woody, ovoid to globular, including scales and bracts arranged around a central axis, especially in conifers an ...
covered in ice
File:Tree branch after ice storm.JPG, A buildup of ice on a branch after an ice storm
File:Car Ice Storm.jpg, Car after an ice storm
File:Freezing Willow.JPG, A weeping willow
''Salix babylonica'' (Babylon willow or weeping willow; ) is a species of willow native to dry areas of northern China, but cultivated for millennia elsewhere in Asia, being traded along the Silk Road to southwest Asia and Europe.Flora of China'' ...
tree damaged by an ice storm
See also
*
Freezing rain
Freezing rain is rain maintained at temperatures below freezing by the ambient air mass that causes freezing on contact with surfaces. Unlike a mixture of rain and snow or ice pellets, freezing rain is made entirely of liquid droplets. The raind ...
*
Ice pruning
Ice pruning is the natural process of selective vegetative pruning on the windward side of a plant, executed by the impact of ice and snow particles driven by wind.William M. Marsh (1978) ''Environmental Analysis: For Land Use and Site Planning'', ...
*
List of ice storms
This is a list of notable ice storms.
1940s
*Great Ice Storm of November 23–25, 1940.
1970s
*Twin North Carolina Ice Storms of January 12–13 and 19-20, 1978
1990s
*Western and Northern NY Ice Storm of March 3–4, 1991
*January 1998 Nort ...
*
Power outage
A power outage (also called a powercut, a power out, a power failure, a power blackout, a power loss, or a blackout) is the loss of the electrical power network supply to an end user.
There are many causes of power failures in an electricit ...
*
Sperry–Piltz Ice Accumulation Index
References
External links
Ice Stormsat
The Weather Channel
The Weather Channel (TWC) is an American pay television channel owned by Weather Group, LLC, a subsidiary of Allen Media Group. The channel's headquarters are in Atlanta, Georgia. Launched on May 2, 1982, the channel broadcasts weather forecas ...
U.S. Billion-dollar Weather and Climate Events
{{DEFAULTSORT:Ice Storm
Road hazards
Snow or ice weather phenomena