Severe Weather, a Year Round Property Threat
How Ice Damages Roofs
When ice storms strike, thick layers of ice encase trees and weigh down branches, often to the breaking point. Fallen trees and branches can cause severe damage to your roof system, tearing through shingles and puncturing the wooden roof decking that supports them. They can also bring down power lines and block roads, making it difficult to access properties and address damage.
Another serious ice storm problem: ice dams on the roof. Generally, these form owing to poor attic ventilation. When interior hot air rises to your attic, it warms the roof, which helps melt the snow and ice accumulated on the rooftop. The ice melt then runs down to the edges of the roof or near the gutters to an area that is not warmed by trapped and heated attic airspace. The water pools and refreezes into a dam; this expands and forms wedges of ice that push apart roofing components and create an entry point for moisture to further damages the roof and the interior of the home.
When moisture is introduced to these areas, the likelihood of mold growth is high. This can lead to an unhealthy situation. Damage of this kind is costly and results in the need for a partial or total roof replacement.
How to Prepare for Ice Storms
The best way to prepare for an ice storm is to be proactive. Keep your roof edges and gutters clear of debris. Clogged gutters cause ice to accumulate, which can push debris under the roof edge. This creates an entry point for moisture, bacteria, insects, and even squirrels and bats. Hire a professional to trim back tree branches close to the roof to avoid the accumulation of leaves, as well as possible damage and personal injury from falling limbs.
How Ice Storms Form
Ice storms occur when a layer of warm air becomes sandwiched between two layers of cold air. The top cold layer creates frozen water particles; when these reach the middle section of warm air, the frozen water melts. The liquid then falls into the second layer of cold air and refreezes before hitting the ground. In this case, the frozen precipitation is referred to as sleet, which causes extremely slippery conditions on outdoor surfaces.
Rain droplets that do not refreeze before touching a surface are called ‘super-cooled drops.’ Cold precipitation can quickly refreeze as it meets surfaces at or below freezing. This process is called freezing rain, which causes a glazing of ice to form. Winter storms are generally categorized as ice storms when ice accumulates to a quarter of an inch or more, according to the National Weather Service1.
Ice Storm Facts & Figures
Many ice storms occur in the New England area but, in recent years, shifting weather patterns have brought ice storms to the southern plains and Southeast. According to the Insurance Information Institute, there were nine major winter storms in 2018, resulting in $4.2 billion in total losses and $3 billion in insured losses.
The North American ice storm of 19982 was the most destructive in recent history. Dangerously thick coatings of ice contributed to power loss in over 3 million households, with some outages lasting more than six weeks.
A 2009 ice storm centered from northern Arkansas to the Ohio Valley knocked out power services to 1.3 million people.
In 2014, a massive winter storm brought snow and ice to the southern states3, then quickly moved up the East Coast. In its wake there were at least 22 deaths4, and 1.2 million homes lost power.
Read More: Tips for Winterizing your Home
Sources
1.https://forecast.weather.gov/glossary.php?word=ICE%20STORM
2.https://weather.com/en-CA/canada/news/news/2018-01-03-ice-storm-damage-impacts-20121123
3.https://www.ajc.com/weather/remembering-snow-jam-2014-the-numbers/xGVwkyBhoebgNaTAmfGfUO/
4.https://www.bbc.com/news/world-us-canada-26182797
