Wind as a concept – air masses moving between areas of high and low pressure – seems straightforward. Wind in reality displays outrageous variation. Spring handily illustrates the changeable nature of this force of nature: it’s a very windy time of year in North America. Why? The jet stream lifts north. Higher sun angles warm the ground and air, creating convection currents. As warm and humid air pushes against cold and dry air, strong areas of low pressure develop. The Coriolis effect adds a push to traveling air masses as well.
“Commercial property owners must be alert to risks of wind damage in the Spring,” says Darren Impson, President at Paul Davis of Tampa. “Wind interacts with buildings differently depending on many factors. Exposed structures – those with few buildings or trees nearby – are at greater risk. So are multi-story buildings and those with broad, flat profiles. Topography – is your property at the bottom of a slope, or higher in elevation? – makes a difference, too.”
Impson recommends that owners keep a sharp eye on spring forecasts. “We track the weather carefully,” he says, “and it behooves commercial property owners to do the same so they can prepare if necessary.” He also advises knowing the seven type of wind events and how prevalent they are in your region:
Straight-line: this very common wind event is found throughout North America, with speeds ranging from a light breeze to sustained high-force gales. Derechos, a particularly devastating straight-wind storm that can last hours and push across thousands of kilometers, may cause tremendous damage. The center of the continent is at highest risk for this wind event.
Down-slope: Found in mountainous regions such as Alaska and Colorado, down-slope winds are just what they sound like: winds that race down high slopes due to temperature and humidity changes as air moves over mountain ranges. They can be high speed with sudden gusts that can be particularly damaging to property.
Thunderstorms: These violent storms are the most frequent cause of wind damage on commercial properties, causing 80% of insured losses in recent years. Thunderstorms, which can inflict extreme damage in minutes, occur across North America. They can also spawn our next devastating type of wind event.
Tornadoes: These violently rotating windstorms are most common in the eastern-central areas of the continent, with the vast majority of tornadoes occurring in the United States. They cluster in warmer seasons but last month, a blockbuster winter storm produced a rare tornado in North Carolina.
Downburst/Microburst: These wind events are powerful downdrafts associated with an estimated five percent of thunderstorms. They are short – 15-20 minutes – and occur in a circular area from 2,000 to 4,000 meters across. They can occur anywhere in North America and may wreak extraordinary damage in minutes.
Nor’easter: Cold and violent, these occur along the Northeastern seaboard, usually forming in the latitudes between Georgia and New Jersey and attaining peak wind speeds as they travel north through New England and Canada’s Maritime Provinces. Multi-day nor’easters are not uncommon.
Hurricane: Also occurring in the eastern regions, these circular storms can span 80 to an astonishing nearly 1,000 kilometers in circumference with wind speeds from 120 to 250 kilometers per hour or higher. Those closest to the coast are at highest risk; peak winds typically last for several hours in a single location.
To learn more about protecting your property against wind damage, call your local Paul Davis office or 844-215-7898 for more information.