Why Freezing Rain Can Be More Dangerous Than Snow
Freezing rain can cause ice to accumulate on tree branches and power lines, posing a greater risk than snow. This past weekend’s winter storm covered large parts of the country with snow, with some areas receiving up to two feet of snow. However, the widespread power outages that occurred were not primarily due to the snow but rather to the 0.5 to one inch of ice that formed as a result of freezing rain.
Freezing rain occurs when there is a layer of warm air between higher levels of the atmosphere and the surface, causing snow to melt into rain. If there is a deep enough layer of freezing air below this warm layer, the rain refreezes into ice pellets known as sleet. When the rain freezes on contact with cold surfaces like bridges, tree branches, and power lines, it becomes freezing rain.
The recent winter storm in the southern U.S. saw warm, moist air from the Gulf of Mexico melt the snow into freezing rain, which then hardened into ice on the ground. Unlike snow, which can be blown off surfaces by wind, ice sticks to surfaces, exerting significant weight. Ice accumulation on power lines can add up to 500 pounds, making them susceptible to breakage.
Power outages occur when ice breaks power lines or tree limbs that in turn damage the power lines. Areas with aboveground power lines are more vulnerable to outages, with research showing that underground lines are more prevalent in wealthier neighborhoods. This socioeconomic disparity means that people in poorer areas are more likely to experience longer outages and may not have access to backup generators.
The recent storm highlighted the impact of ice accumulation on power infrastructure, especially in rural areas where power outages affected a significant portion of the population. Recovery from such outages can be prolonged due to the extensive damage caused by ice accumulation, requiring repair crews to navigate icy roads and snow-covered terrain.
In conclusion, freezing rain poses a greater risk to infrastructure than snow due to its ability to accumulate ice on surfaces, leading to power outages and significant damage. Understanding the mechanisms behind freezing rain can help communities better prepare for and respond to winter storms to minimize the impact on essential services.
