Winter Weather - Impacts | State Climate Office of North Carolina

Impacts of Winter Weather

Why do we need to care about winter weather in North Carolina? The reason is that although winter weather may seem harmless, and oftentimes fleeting for the majority of the state, the underlying hazards can significantly impact everyday life. The impacts of winter weather can essentially be broken down into two categories:

Areas: how does winter weather affect your environment?

People: how can winter weather directly impact you?

A. Areas

1) Roads

70% of winter weather related injuries are the result of vehicle accidents. A thick blanket of snow or ice on roads makes driving difficult, and a bad idea. If the road is covered by a blanket of snow, it is difficult to determine where the road ends and a ditch or other hazard begins; driving becomes even more perilous when two cars are attempting to travel down a road with no visible lanes, and inclined roads can become impassible. In the event of an accident, drivers may be stranded for many hours in harsh weather conditions waiting for assistance.

Freezing rain and sleet can dramatically worsen the driving hazard by creating a dangerously slick, icy road surface.

Clearing ice or snow covered roads is also a problem; with limited equipment in NC due to the relative infrequency of events, priority is given to main thoroughfares and secondary roads are largely untouched during the initial hours after a storm has passed.

Black ice is also a major hazard associated with frozen precipitation on roads, and it doesn’t begin until the storm has ended! When snow and ice begin to melt, the resultant liquid can linger on the roadways until night, and if temperatures fall below freezing can refreeze creating a thin sheet of ice that is impossible to see. It is called black ice because of the fact that it blends in with the road surface, and is very difficult to detect while driving.

The melting/refreezing process can occur for many days after a storm, and will only end once all moisture is melted and evaporated, and roads are dry.

2) Ice Accrual

Freezing rain accumulation on trees can cause large limbs, or even whole trees, to snap and possibly fall on homes, cars, or power lines. This also creates a very dangerous environment to be outside in; if a large limb snaps while you’re driving or walking underneath it, significant injury can occur.

The other major concern in icing from freezing rain events is power outages; when large amounts of ice accumulate on power lines and poles, widespread outages are likely to occur.

The results of significant icing can be economically and sociologically devastating; power companies that are not properly prepared for such an event may not be able to restore power to everyone for many days, which leaves thousands of customers shivering in often brutally cold weather, resulting in potentially dangerous attempts to heat their homes. Businesses without power are forced to shut down, resulting in huge financial losses for the local economy.

B. People

1) Visibility

Heavy snow can create dangerous driving conditions by severely limiting the visibility of drivers, sometimes to mere feet!. This is commonly referred to as "white out" conditions. During moderate to heavy snowfall, visibilities can be reduced to as little as 0 to .25 miles. The lack of visibility combined with slick, snow covered roads greatly increases the probability of an accident.

2) Loss of Power (Heating Hazards)

Residents can lose power during a winter storm when snow or ice accumulates on trees and causes them to fall onto a power line, or if enough ice accrues on a power line it may simply collapse on its own.

Power outages during very cold conditions can result in a potentially dangerous situation. If the power is out for a prolonged period, residents are forced to find alternative means to heat their homes. The danger arises from carbon monoxide poisoning, which is a scentless, deadly gas released from improperly ventilated heating sources such as space or kerosene heaters, furnaces, water heaters, gas stoves, fireplaces, and blocked chimneys. The danger can be prevented by providing proper maintenance and ventilation.

3) Dangerously Cold Temperatures

Dangerously cold temperatures, although uncommon, do occur in NC winters. When a cold air outbreak sends temperatures down into the teens and single digits, it becomes much more dangerous to be outside for prolonged periods.

Some of the major threats include:

Wind Chill: a measure of what the temperature feels like when accounting for the wind speed. As the wind increases, more heat is able to be removed from your body by the wind.

Frostbite: results from prolonged exposure to very cold air. Injury is caused by freezing body tissue; extremities such as the fingers and toes are the most susceptible to frostbite.

Hypothermia: similar to frostbite, this occurs when the body has been exposed to prolonged cold. The onset of hypothermia occurs when the body temperature drops below 95°F.

4) Aircraft Icing

Icing poses a major threat to air travel. When aircraft fly through clouds with supercooled water droplets, ice can accrete on the plane’s wings or engines, and according to NASA reports can increase drag on the plane and lead to engine failure.

Less than a millimeter of ice on the wing can reduce lift by 25%!

Results in lengthy flight delays and cancellations.

Introduction

Precipitation Types

Atmospheric Patterns

Winter Storm Database

Climatology