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Cold waves and mitigation strategies

A cold wave is an extended period of below-normal temperatures.

Cold Waves

• Winter high-pressure systems are much more influenced by the jet stream than are summer systems and therefore rarely linger over one

area.

Highly amplified upper level ridge-trough system over North America.

Positive surface pressure anomalies due to an anticyclone that propagates southward from western Canada to the Gulf Coast.

Extensive snow cover over northern and central North America to keep the arctic airmass insulated.

Intensity of CAO most related to strength of anticyclone or its associated cold air advection.

Cold wave Characteristics

Results of Cold Weather Injuries◦ Napoleon and Hitler both lost Russia due to Cold Weather

Injuries.

In the Korean War◦ 8,000 cold weather casualties the first winter.

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Historical Information

On average, 35 deaths per year directly related to the extreme cold.

Economic losses can be in the billions Heating costs increase considerably Transportation related issues

Why Do We Care about Extreme Cold Waves?

Rank cold waves quantitatively based on:

1. Duration2. Intensity3. Coverage area

Objective Cold Wave Ranking Criteria

Several polar high-pressure systems can follow the same path and subject the same areas to bout after bout of numbing cold.

3. Which type of air masses are usually responsible for cold waves?

Section Assessment

Cold waves are caused by air masses of continental polar or arctic origin.

Incidence of 2007 Cold Wave in South AsiaA cold wave is an extreme cold weather condition, which can cause death and injury to humans andanimals. A major cold wave was triggered in northern India and Bangladesh in 2007. Temperaturesclose to freezing point claimed many lives in India and Bangladesh. In Nepal, temperatures acrossthe southern plains were reported as around 12°C below normal. On 14 February, Kathmandu receivedits first snowfall in 63 years.

Cold Wave in Bangladesh, 2007In Bangladesh, the cold wave killed more than 20 people in December 2007. Most of them diedwithin 48 hours. The country’s lowest temperature of 8.6 degree was recorded at Rajshahi.5In first week of January 2007, a severe cold wave swept through most parts of Bangladesh, especiallythe northern and northwestern districts, and affected thousands of vulnerable people ill-preparedto cope with cold conditions. According to local media sources, more than 100 cold-related deathswere reported.6

Cold Waves in California? The coldest air was forced by topography to track just to the eastof the Rocky Mountains. Oscassionaly, a cold airmass may be deep enough to spill overthe Rockies, with cold air entering the Great Basin from thenortheast and affecting Nevada and Utah.In such situations, the sub-freezing air can damage the corpsgrown in California's Central Valley, as in January 2007. However, the downslope (adiabatic) motion results in sufficientadiabatic compression that air temperature in Coastal cities SF,LA, SD) typically will warm considerably.

Major Factors for Cold Outbreaks over US Buildup of a ridge in the jetstream level over western NorthAmerica. Formation of a surface high-pressure center over northernCanada or Alaska. Movement of the cold airmasses in response to steering by theupper-level winds. A mechanism to enhance the winds that transport the cold airsoutheastward. The triggering mechanism is often a strongwinter cyclone crossing central or eastern North America.

Extensive snow cover over central North America to keep thepolar airmasses “refrigerated”.

Typical Upper-Level Pattern

(Severe and Hazardous Weather. Rauber, Walsh, Charlevoix, 2002)

1. Stay warm2. Avoid slips and falls3. Use care when shoveling snow4. Operate snow blowers safely5. Plowing safety6. Safety when applying salt/antiskid7. Summary

Cold Wave in India, 2007In early 2007, cold wave killed two inJaunpur in the north Indian state ofUttar Pradesh. The cold wave continuedthroughout January. Cold waves in mostpart of north India resulted intemperatures dropping to less than 3-5OC of the average temperature, whichclaimed more than 90 people lives,especially in Uttar Pradesh.7 The coldwave also prevailed in Jammu andKashmir from 11 March to 14 March2007. As per EMDAT data, sixty-sixpeople were killed from the extremecold waves. Further, from second weekof December 2007, north India was inthe grip of a cold wave. Large areas overnorth India recorded temperatures below normal. Forty-seven people were killed by the cold wavein Uttar Pradesh), where cities recorded temperatures between 0 and 5OC in 2007

Incidence of 2007 Cold Wave in South AsiaA cold wave is an extreme cold weather condition, which can cause death and injury to humans andanimals. A major cold wave was triggered in northern India and Bangladesh in 2007. Temperaturesclose to freezing point claimed many lives in India and Bangladesh. In Nepal, temperatures acrossthe southern plains were reported as around 12°C below normal. On 14 February, Kathmandu receivedits first snowfall in 63 years.

Non Freezing◦ Hypothermia◦ Chilblains◦ Trench/Immersion foot

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Cold Weather Injuries

Associated Injuries– Snow Blindness– Dehydration

Freezing– Frost nip– Frostbite

First aid and Preparation for Cold WaveThe victim should be covered with warm blankets and he should be taken indoors. Warm the victim slowly as rapid warming can cause severe heart problems. People can prepare themselves when they know about cold waves through weather forecast.

Immediate Care:Firstly, cover the victim with warm blankets.The victim should be moved inside the house.Room heaters should be put on.Warm broth and soup must be given.Hot bath can also be given.Soak the victims feet in warm water.Drink warm, non-alcoholic beverages.Chemical heat packs can be applied on the neck and armpits of the victim.Warm the victim, slowly as rapid warming may lead to serious heart problems.If the victim is not recovering, call for the emergency medical services.Make the victim take rest.Do not allow the victim to walk.

Preparation for cold wave:People can store water, food and other needed things before a cold wave.Suitable stocks of forage can be secured before cold waves for livestock.The crops that are vulnerable can be sprayed with water.This procedure protects the plants by freezing and absorbing the cold from surrounding air.The freezing of water releases heat that protects the fruit.Smudge pots can be used.The hospitals can prepare for the admission of victims affected by cold wave.Wear clothes that make you feel warm.Dress in layers if going outside.Store candles, flashlights, portable fuel and matches for wood used in fire places or stoves.NOTE:The use of charcoal for cooking or heating is a dangerous thing as there is a risk for carbon monoxide poisoning.

Thank you