Severe Winter Weather
Severe Winter Weather often involves cold temperatures, icy roads, utility power failures, loss of Internet and other services, and can be sufficiently impactful to cause personal injuries or loss of life, significant crop or other property damage, and/or disruption to commerce or transportation.
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Severe winter weather can occur almost anywhere in the U.S. and is a combination of unusually cold temperatures combined with snow, sleet, or freezing rain. When these conditions lead to injury or loss of life, widespread power failures, property damage, and/or disruptions to transportation and commerce then it is classified as severe winter weather.
Severe winter weather includes unusually cold temperatures and wind chills combined with snow, sleet, and freezing rain that leads to injury or loss of life, widespread power failures, property damage, and/or disruptions to transportation, the ability to work from home, and commerce. The most common types of property damage are roof damage or collapse due to snow, ice, or sleet, and water damage from burst pipes, or “ice dams.” Ice dams occur when water fails to flow properly through gutters, causing it to back up and seep into ceilings and walls. Severe winter storms can produce a variety of dangerous conditions including blizzards, ice storms, lake effect storms, and snow squalls. Unusual atmospheric events like Nor’easters and a southern shift in the polar vortex can also produce severe winter weather.
Categories of Severe Winter Weather#
While the danger from severe winter weather varies by region and is more common in northern states,nearly all of the U.S. is susceptible to one or more forms of severe winter weather. In addition, the consequences of severe winter weather also vary by region. In the northern regions of the U.S. where severe winter weather is more common, the infrastructure and services tend to be better prepared making recovery often more rapid than in regions like the South Central U.S. where severe winter weather is less common.
|Blizzards||A combination of blowing snow and wind that can result in dangerously low visibility.|
|Ice Storms||At least ¼” of ice on exposed surfaces that leads to dangerous driving conditions and can break branches and bring down power lines.|
|Lake Effect Storms||Mainly occur to the south and east of the Great Lakes and are produced when moisture is drawn into a storm as air moves over the Great Lakes and then is released as snow. The same phenomenon occurs on a smaller scale adjacent to the Great Salt Lake in Utah and is responsible for increasing snowfall during 4-5 storms per year.|
|Snow Squalls||Brief intense periods of snow typically accompanied by wind.|
|Nor’easters||Form along the east coast when cold arctic air collides with warmer air over the Atlantic Ocean. This leads to strong winds out of the northeast and moisture from offshore that can produce snow, sleet, or rain. Onshore winds from a Nor’easter can produce rough seas and coastal flooding.|
|Polar Vortex||A swirling mass of cold air that sits above the north pole and typically extends south into northern Canada where it is partially held in place by the polar jet stream. In some winters the polar vortex becomes unstable and pushes south bringing unusually cold temperatures far south into the U.S.|
Health and Safety#
Exposure to severe winter weather can lead to hypothermia, windburn, and frostbite. Indirectly, there is an increase in the risk of car accidents from snow-covered or icy roads, carbon monoxide poisoning from the use of portable heating sources, and heart attacks from over-exertion. On average, about 60 people per year die, and hundreds are injured in the U.S. as a result of severe winter weather.
The National Weather Service produces Winter Storm Advisories, Watches, and Warnings from 12-48 hours before severe winter weather is expected that include information on snowfall, freezing temperatures, wind chills, and freezing rain. In addition, they calculate a Winter Storm Severity Index (WSSI) using snowfall on a six-step scale that predicts the impact of a storm on safety and property.
National Weather Service Winter Storm Severity Index (WSSI)#
|WSSI Scale||Potential Winter Storm Impacts|
|No Impacts||Impacts not expected.|
|Limited Impacts||Rarely a threat to life and property. Typically results in little inconveniences.|
|Minor Impacts||Rarely a direct threat to life and property. Typically results in an inconvenience to daily life.|
|Moderate Impacts||Often threatening to life and property, some damage unavoidable. Typically results in an inconvenience to daily life.|
|Major Impacts||Extensive property damage likely, life-saving actions needed. Will likely result in major disruptions to daily life.|
|Extreme Impacts||Extensive and widespread severe property damage, life-saving actions will be needed. Results in extreme disruptions to daily life.|
Although damage caused by severe winter weather can be significant, the frequency of severe winter weather does not appear to have an effect on property values.The main impact of severe winter weather on property is direct damage from snow, ice, water, and cold temperatures. Some regions experience a decrease in home sales during winter months in general and severe winter weather in particular. Additional costs to homeowners related to severe winter weather can be significant--including snow and ice removal from driveways and walkways and increased energy use for heating.
What You Can Do#
Keep track of severe winter weather forecasts from the National Weather Service and be prepared. The Federal Emergency Management Agency (FEMA) recommends staying off roads, staying indoors and dressing warmly, and looking for signs of hypothermia and frostbite. Additional recommendations are to be prepared for power outages, listen for emergency information and alerts, avoid overexertion to decrease the risk of heart attack, only use generators outside, and check on neighbors.
Prepare your home for severe winter weather with insulation, caulking, and weather stripping. Learn how to prevent ice damming on your roof and how to keep water pipes from freezing. Install and test smoke alarms and carbon monoxide sensors with battery backups, consider investing in a generator and WiFi hotspot, fill the fuel tanks in your vehicles, and gather supplies in case you need to remain at home for several days without power. The National Weather Service recommends a flashlight and extra batteries, a battery-powered portable radio to receive emergency information, extra food that does not require cooking or refrigeration, water, extra medicine and baby items, first aid supplies, an emergency heat source, extra heating fuel and/or propane, and a fire extinguisher.
Most standard homeowners insurance policies provide coverage for winter-related storm damage from wind, snow, ice, freezing rain, and severe temperatures. In some cases and regions, there are exclusions, especially related to wind and water damage. Review your homeowners policy to find out which winter-related home damages are covered.
AreaHub’s Knowledge Center is updated regularly and provides information drawing upon scientific studies and sources.
- NOAA National Severe Storms Laboratory: “Severe Winter Weather.”
- NOAA National Weather Service (NWS): “Nor’easter.”
- NOAA NWS: “Polar Vortex.”
- NOAA NWS: “Winter Storm Severity Index.”
- NOAA NWS: “Weather Related Fatality and Injury Statistics.”
- FEMA Technical Document: “National Risk Index.”
- FEMA: “Preparing for a Winter Storm.”
- Ready-US Government: “Winter Weather.”
- Weather and Forecasting--Journal of the American Meteorological Society: “Great Salt Lake–Effect Precipitation: Observed Frequency, Characteristics, and Associated Environmental Factors.”
- NOAA National Weather Service: “Winter Weather Safety Kit.”