路上黑冰严重, 开车要小心
- 主题发起人 yy123456
- 开始时间
rottenmelon
资深人士
- 注册
- 2016-12-06
- 消息
- 7,534
- 荣誉分数
- 1,918
- 声望点数
- 223
升温了...天气暖和了
m234
⭐安定门箭楼⭐
- 注册
- 2005-01-01
- 消息
- 4,335
- 荣誉分数
- 1,324
- 声望点数
- 373
黑冰不只是冻雨.
气温在-18 C以下时, 路口等红灯车的尾气就能造成黑冰.
这种黑冰不容易看出来,但很滑, 造成路口停车难.
我遇到过一次, 一个路口停车线前二三十米都很滑.
At low temperatures (below −18 °C [0 °F]), black ice can form on roadways when the moisture from automobile exhaust condenses on the road surface.
https://en.wikipedia.org/wiki/Black_ice
最后编辑:
http://ottawacitizen.com/news/local...ick-roads-closes-hwy-7-west-of-carleton-place
MEGAN GILLIS
More from Megan Gillis
Published on: January 2, 2018 | Last Updated: January 2, 2018 10:53 AM EST
Ottawa Paramedics responded to a call for reported vehicle collision and rollover that occurred on the 417 Eastbound, just West of Moodie Drive.
SHAREADJUSTCOMMENT
https://twitter.com/TA_Milne/status/948197025387909125
T.A. Milne@TA_Milne
@Ornge onscene Hwy 7 west of Carleton Place. Slow down on your morning commute. Major black ice this morning. The salt is not working at these temperatures. #besafe #leaveextratime#viewsfromthecrew
9:19 AM - Jan 2, 2018
Twitter Ads info and privacy
Paramedics and firefighters had to use off-road vehicles and high-angle rescue techniques to free the occupants of a vehicle that went down a steep embankment after a crash on Highway 417 near Moodie Drive Tuesday morning.
It took “extensive” manpower to get the patients back through a tunnel under the highway, paramedics said.
Four patients were treated for minor injuries sustained in the crash and exposure to the cold.
The driver of the vehicle, a 48-year-old woman, had a back and lower-leg injury. A 77-year-old woman had lower leg and a hand injury and complications of diabetes. A 77-year-old man had neck and back pain.
A fourth man was assessed by paramedics and was unhurt.
Paramedics called in fire crews at 7:55 a.m. after the crash in the eastbound lanes sent one of the vehicles over a railingand down the slope. Paramedics say the vehicle was at the bottom of an approximately 30-metre hill.
Firefighters had to use cutters and spreaders to free three people from the damaged vehicle then carried each one up the hill using Stokes baskets. All three were freed by 8:38 a.m.
Watch for black ice and be aware of driving conditions, Ottawa police warned.
Multiple accidents on the 417 caused a slow commute Tuesday January 2, 2018, including this truck pointing the wrong direction on the westbound 417 near Carling. -
4h
OPPCommunicationsER
✔@OPP_COMM_ER
COLLISION: #Hwy7 near Ramsay Concession 1 #Innisville - 2 vehicles, Hwy blocked ^jp
https://twitter.com/OPP_COMM_ER/status/948173383140872197
OPPCommunicationsER
✔@OPP_COMM_ER
UPDATE ROAD CLOSURE: #Hwy7 between Ramsay Concession 1 and Ferguson Falls Rd #Innisville - Hwy CLOSED due to collision ^jp
7:45 AM - Jan 2, 2018
Twitter Ads info and privacy
As of 7:45 a.m. as the commute got underway in earnest, the OPP and the City of Ottawa’s traffic centre were warning of snarls including:
MEGAN GILLIS
More from Megan Gillis
Published on: January 2, 2018 | Last Updated: January 2, 2018 10:53 AM EST
Ottawa Paramedics responded to a call for reported vehicle collision and rollover that occurred on the 417 Eastbound, just West of Moodie Drive.
SHAREADJUSTCOMMENT
https://twitter.com/TA_Milne/status/948197025387909125
T.A. Milne@TA_Milne@Ornge onscene Hwy 7 west of Carleton Place. Slow down on your morning commute. Major black ice this morning. The salt is not working at these temperatures. #besafe #leaveextratime#viewsfromthecrew
9:19 AM - Jan 2, 2018
Twitter Ads info and privacy
Paramedics and firefighters had to use off-road vehicles and high-angle rescue techniques to free the occupants of a vehicle that went down a steep embankment after a crash on Highway 417 near Moodie Drive Tuesday morning.
It took “extensive” manpower to get the patients back through a tunnel under the highway, paramedics said.
Four patients were treated for minor injuries sustained in the crash and exposure to the cold.
The driver of the vehicle, a 48-year-old woman, had a back and lower-leg injury. A 77-year-old woman had lower leg and a hand injury and complications of diabetes. A 77-year-old man had neck and back pain.
A fourth man was assessed by paramedics and was unhurt.
Paramedics called in fire crews at 7:55 a.m. after the crash in the eastbound lanes sent one of the vehicles over a railingand down the slope. Paramedics say the vehicle was at the bottom of an approximately 30-metre hill.
Firefighters had to use cutters and spreaders to free three people from the damaged vehicle then carried each one up the hill using Stokes baskets. All three were freed by 8:38 a.m.
Watch for black ice and be aware of driving conditions, Ottawa police warned.
Multiple accidents on the 417 caused a slow commute Tuesday January 2, 2018, including this truck pointing the wrong direction on the westbound 417 near Carling. -
4h
OPPCommunicationsER✔@OPP_COMM_ER
COLLISION: #Hwy7 near Ramsay Concession 1 #Innisville - 2 vehicles, Hwy blocked ^jp
https://twitter.com/OPP_COMM_ER/status/948173383140872197
OPPCommunicationsER✔@OPP_COMM_ER
UPDATE ROAD CLOSURE: #Hwy7 between Ramsay Concession 1 and Ferguson Falls Rd #Innisville - Hwy CLOSED due to collision ^jp
7:45 AM - Jan 2, 2018
Twitter Ads info and privacy
As of 7:45 a.m. as the commute got underway in earnest, the OPP and the City of Ottawa’s traffic centre were warning of snarls including:
- A collision on westbound Highway 417 at Carling Avenue blocking the left lane as a tow truck removed a vehicle, while another crash at Island Park Drive blocked the right lane eastbound
- Collisions in both the westbound and eastbound lanes of Highway 417 at Nicholas Street has just been cleared
https://en.wikipedia.org/wiki/Black_ice
Black ice, sometimes called clear ice, is a thin coating of glaze ice on a surface, especially on roads. The ice itself is not black, but visually transparent, allowing the often black road below to be seen through it. The typically low levels of noticeable ice pellets, snow, or sleet surrounding black ice means that areas of the ice are often practically invisible to drivers or people stepping on it. There is, thus, a risk of skidding and subsequent accident due to the unexpected loss of traction.
Contents
[1Definitions
Definitions[edit]
The term black ice in the United States is often incorrectly used to describe any type of ice that forms on roadways, even when standing water on roads turns to ice as the temperature falls below freezing. Correctly defined, black ice is formed on relatively dry roads, rendering it invisible to drivers. It occurs when in the textures present in all pavements very slightly below the top of the road surface contain water or moisture, thereby presenting a dry surface to tires until that water or moisture freezes and expands; drivers then find they are riding above the road surface on a honeycombed invisible sheet of ice.
Three other definitions of black ice by the World Meteorological Organization are:[1]
On roads and pavements[edit]
The American Meteorological Society Glossary of Meteorology includes the definition of black ice as "a thin sheet of ice, relatively dark in appearance, [that] may form when light rain or drizzle falls on a road surface that is at a temperature below 0 °C (32 °F)."[2] Because it represents only a thin accumulation, black ice is highly transparent and thus difficult to see as compared with snow, frozen slush, or thicker ice layers. In addition, it often is interleaved with wet pavement, which is nearly identical in appearance. This makes driving, cycling or walking on affected surfaces extremely dangerous. Deicing with salt (sodium chloride) is effective down to temperatures of about −18 °C (0 °F). Other compounds such as magnesium chloride or calcium chloride have been used for very cold temperatures since the freezing-point depression of their solutions is lower.
At low temperatures (below −18 °C [0 °F]), black ice can form on roadways when the moisture from automobile exhaust condenses on the road surface.[3] Such conditions caused multiple accidents in Minnesota when the temperatures dipped below −18 °C (0 °F) for a prolonged period of time in mid-December 2008.[4]Salt's ineffectiveness at melting ice at these temperatures compounds the problem. Black ice may form even when the ambient temperature is several degrees above the freezing point of water 0 °C (32 °F), if the air warms suddenly after a prolonged cold spell that has left the surface of the roadway well below the freezing point temperature.
On December 1, 2013, heavy post-Thanksgiving weekend traffic encountered black ice on the westbound I-290 expressway in Worcester, Massachusetts. A chain reaction series of crashes resulted, involving three tractor-trailers and over 60 other vehicles. The ice formed suddenly on a long downward slope, surprising drivers coming over the crest of a hill, who could not see crashed vehicles ahead until it was too late to stop on the slick pavement.[5]
On bridges[edit]
Warning sign for bridge on US turnpike
Bridges and overpasses can be especially dangerous. Black ice forms first on bridges and overpasses because air can circulate both above and below the surface of the elevated roadway when the ambient temperature drops, causing the bridge pavement temperature to fall more rapidly.[6]
In the United States, road warning signs with the advisory "Bridge May Be Icy" indicate potentially dangerous roadways above bridge structures.
Similar road signs exists throughout Canada, but warnings sometimes appear without words to comply to bilingual requirements. The Canadian sign features a vehicle with skid marks and snow flakes. The same sign's official and undisclosed description is defined as "Pavement is slippery when wet".[7]
Additional signs may be attached with various different wording in Canadian provinces that do not have bilingual requirements:
See also: I-35W Mississippi River bridge
The I-35W Mississippi River bridge seen from below in 2006
The I-35W Mississippi River bridge in Minneapolis, Minnesota, was well known for its black ice before it collapsed in 2007 into the Mississippi River. It had caused several pileups during its 40-year life. On December 19, 1985, the temperature reached −34 °C (−29 °F). Cars crossing the bridge experienced black ice and there was a massive pile up of crashed vehicles on the bridge on the northbound side. In February and in December 1996, the bridge was identified as the single most treacherous cold-weather spot in the local freeway system, because of the almost frictionless thin layer of black ice that regularly formed when temperatures dropped below freezing. The bridge's proximity to Saint Anthony Falls contributed significantly to the icing problem and the site was noted for frequent spinouts and collisions.[8][9]
By January 1999, Mn/DOT began testing magnesium chloride solutions and a mixture of magnesium chloride and a corn-processing byproduct to see whether either would reduce the black ice that appeared on the bridge during the winter months.[10]In October 1999, the state embedded temperature-activated nozzles in the bridge deck to spray the bridge with potassium acetate solution to keep the area free of winter black ice.[11][12] The system came into operation in 2000.[13][14]
While the automated de-icing system prevented further major multi-vehicle collisions, it may have contributed to the collapse of the I-35W bridge, due to accelerated corrosion of the structure.[15]
On water[edit]
Main article: Congelation ice
Black ice on a canal in the Netherlands
When the temperature is below freezing and the wind is calm, such as under a high atmospheric pressure at night in the fall, a thin layer of ice will form over open water of a lake. If the depth of the body of water is large enough, its color is black and can be seen through the ice, thus the name black ice.
Ice can also be formed by seawater spray and water vapour freezing upon contact with a vessel's superstructure when temperature is low enough. Ice formed in this manner is known as rime.[16] As the formation progress, the aboveboard weight of the vessel increases and may ultimately cause capsizing. Furthermore, rime ice may impede the correct functioning of important navigational instruments on board, such as radar or radio installations. Different strategies for the removal of such ice are employed: chipping away the ice or even using fire hoses in an attempt to remove the ice.
In mountains[edit]
Main article: Glaze ice
Black ice is a great hazard for climbers and scramblers. Cold weather is common at high altitudes, and black ice quickly forms on rock surfaces. Loss of traction is as sudden and unexpected as on a pavement or road, but can be fatal if the rock is in an exposed position with a drop below. An ice-axe and crampons are essential use in such circumstances as they will help to prevent a fall, and a belay rope will help to arrest a fall.
Black ice, sometimes called clear ice, is a thin coating of glaze ice on a surface, especially on roads. The ice itself is not black, but visually transparent, allowing the often black road below to be seen through it. The typically low levels of noticeable ice pellets, snow, or sleet surrounding black ice means that areas of the ice are often practically invisible to drivers or people stepping on it. There is, thus, a risk of skidding and subsequent accident due to the unexpected loss of traction.
Contents
[1Definitions
Definitions[edit]
The term black ice in the United States is often incorrectly used to describe any type of ice that forms on roadways, even when standing water on roads turns to ice as the temperature falls below freezing. Correctly defined, black ice is formed on relatively dry roads, rendering it invisible to drivers. It occurs when in the textures present in all pavements very slightly below the top of the road surface contain water or moisture, thereby presenting a dry surface to tires until that water or moisture freezes and expands; drivers then find they are riding above the road surface on a honeycombed invisible sheet of ice.
Three other definitions of black ice by the World Meteorological Organization are:[1]
- A thin ice layer on a fresh or salt water body which appears dark in colour because of its transparency;
- A mariner's term for a dreaded form of icing sometimes sufficiently heavy to capsize a small ship;
- Another term for ice on rocks in the mountains known equally as verglas (glaze ice).
On roads and pavements[edit]
The American Meteorological Society Glossary of Meteorology includes the definition of black ice as "a thin sheet of ice, relatively dark in appearance, [that] may form when light rain or drizzle falls on a road surface that is at a temperature below 0 °C (32 °F)."[2] Because it represents only a thin accumulation, black ice is highly transparent and thus difficult to see as compared with snow, frozen slush, or thicker ice layers. In addition, it often is interleaved with wet pavement, which is nearly identical in appearance. This makes driving, cycling or walking on affected surfaces extremely dangerous. Deicing with salt (sodium chloride) is effective down to temperatures of about −18 °C (0 °F). Other compounds such as magnesium chloride or calcium chloride have been used for very cold temperatures since the freezing-point depression of their solutions is lower.
At low temperatures (below −18 °C [0 °F]), black ice can form on roadways when the moisture from automobile exhaust condenses on the road surface.[3] Such conditions caused multiple accidents in Minnesota when the temperatures dipped below −18 °C (0 °F) for a prolonged period of time in mid-December 2008.[4]Salt's ineffectiveness at melting ice at these temperatures compounds the problem. Black ice may form even when the ambient temperature is several degrees above the freezing point of water 0 °C (32 °F), if the air warms suddenly after a prolonged cold spell that has left the surface of the roadway well below the freezing point temperature.
On December 1, 2013, heavy post-Thanksgiving weekend traffic encountered black ice on the westbound I-290 expressway in Worcester, Massachusetts. A chain reaction series of crashes resulted, involving three tractor-trailers and over 60 other vehicles. The ice formed suddenly on a long downward slope, surprising drivers coming over the crest of a hill, who could not see crashed vehicles ahead until it was too late to stop on the slick pavement.[5]
On bridges[edit]
Warning sign for bridge on US turnpike
Bridges and overpasses can be especially dangerous. Black ice forms first on bridges and overpasses because air can circulate both above and below the surface of the elevated roadway when the ambient temperature drops, causing the bridge pavement temperature to fall more rapidly.[6]
In the United States, road warning signs with the advisory "Bridge May Be Icy" indicate potentially dangerous roadways above bridge structures.
Similar road signs exists throughout Canada, but warnings sometimes appear without words to comply to bilingual requirements. The Canadian sign features a vehicle with skid marks and snow flakes. The same sign's official and undisclosed description is defined as "Pavement is slippery when wet".[7]
Additional signs may be attached with various different wording in Canadian provinces that do not have bilingual requirements:
- Bridge Ices
- Slippery When Wet
- Road Ices
- Slippery When Frosty
- Icy Bridge Deck
- Bridge Ices Before Road
See also: I-35W Mississippi River bridge
The I-35W Mississippi River bridge seen from below in 2006
The I-35W Mississippi River bridge in Minneapolis, Minnesota, was well known for its black ice before it collapsed in 2007 into the Mississippi River. It had caused several pileups during its 40-year life. On December 19, 1985, the temperature reached −34 °C (−29 °F). Cars crossing the bridge experienced black ice and there was a massive pile up of crashed vehicles on the bridge on the northbound side. In February and in December 1996, the bridge was identified as the single most treacherous cold-weather spot in the local freeway system, because of the almost frictionless thin layer of black ice that regularly formed when temperatures dropped below freezing. The bridge's proximity to Saint Anthony Falls contributed significantly to the icing problem and the site was noted for frequent spinouts and collisions.[8][9]
By January 1999, Mn/DOT began testing magnesium chloride solutions and a mixture of magnesium chloride and a corn-processing byproduct to see whether either would reduce the black ice that appeared on the bridge during the winter months.[10]In October 1999, the state embedded temperature-activated nozzles in the bridge deck to spray the bridge with potassium acetate solution to keep the area free of winter black ice.[11][12] The system came into operation in 2000.[13][14]
While the automated de-icing system prevented further major multi-vehicle collisions, it may have contributed to the collapse of the I-35W bridge, due to accelerated corrosion of the structure.[15]
On water[edit]
Main article: Congelation ice
Black ice on a canal in the Netherlands
When the temperature is below freezing and the wind is calm, such as under a high atmospheric pressure at night in the fall, a thin layer of ice will form over open water of a lake. If the depth of the body of water is large enough, its color is black and can be seen through the ice, thus the name black ice.
Ice can also be formed by seawater spray and water vapour freezing upon contact with a vessel's superstructure when temperature is low enough. Ice formed in this manner is known as rime.[16] As the formation progress, the aboveboard weight of the vessel increases and may ultimately cause capsizing. Furthermore, rime ice may impede the correct functioning of important navigational instruments on board, such as radar or radio installations. Different strategies for the removal of such ice are employed: chipping away the ice or even using fire hoses in an attempt to remove the ice.
In mountains[edit]
Main article: Glaze ice
Black ice is a great hazard for climbers and scramblers. Cold weather is common at high altitudes, and black ice quickly forms on rock surfaces. Loss of traction is as sudden and unexpected as on a pavement or road, but can be fatal if the rock is in an exposed position with a drop below. An ice-axe and crampons are essential use in such circumstances as they will help to prevent a fall, and a belay rope will help to arrest a fall.
