Tropical Winds & Hurricanes

Tropical Storms and Hurricanes can pack a hurt on Central Virginia. For those who remember 2003’s Hurricane Isabel, a category 1 hurricane, the wind speeds were real. With sustained winds of 75 mph in many areas, power outages occurred rapidly and remained for days, and in some cases, weeks. Whether we are looking at a Tropical Storm or a Hurricane aiming at Virginia, we need to be prepared before the storm!

Hurricane Harvey hit the Texas Coastline with wind and rain, however the greatest impact was the Houston Metro and surrounding areas with flooding due to storm surge and beyond. Irene wreaked havoc on the Virginia coastline causing major flooding, as well as spawning tornadoes. The wind damage caused outages for days and weeks in many areas as far inland as Amelia and Powhatan counties.

Wind damage is many times the hardest impact received in Central Virginia and causes the widespread outages that drive the lengthy power outages. Dominion Energy and the Electric Cooperatives have done an excellent job since Isabel and Irene in cutting back trees along the power lines and upgrading equipment that was prone to failure. These small steps are costly but effective in helping keep power outages to a minimum during normal storm season.

Challenges come when large storms like Isabel, Irene and others that pack wind and are downplayed. Most hurricanes in Central Virginia make their appearances in late August and September right after a rainy end of summer. Saturated ground leaves trees and other ground oriented items somewhat unstable and unable to absorb more rain and withstand the high winds associated with hurricanes and tropical storms. As the ground is saturated, these unstable items become dangerous to the power grid and your home electricity.

We have all witnessed the strength of wind events like the Derecho of 2012 when on a sunny day, the bottom dropped out and so did the wind. Winds fell upon Central Virginia wreaking havoc on everything in its path, leaving central Virginians without power for weeks. In some areas like New Kent County the Derecho was followed by two separate tornado events that left residents without power in some cases for over 30 days, feeling helpless and hopeless.

The Saffir-Simpson Scale – What is it?

The Saffir-Simpson Scale dates back to 1971 when civil engineer Herbert Saffir and meteorologist Robert Simpson of NOAA combined forces to present a unified scale to predict the level of potential damage of hurricanes. Saffir based his portion on the wind speeds and used the U. S. Geological Richter Scale as a guide to keep the scale a simple 1 through 5. Simpson took into account the storm surge and flooding. Together they combined their research to come up with today’s Saffir-Simpson Scale which grades the level of hurricanes and their impact.

Interestingly enough, Saffir was commissioned by the United Nations in 1969 to research the potential damage in hurricane prone area to the low cost housing. In 2009 the Saffir-Simpson Scale was amended to remove the pressure and storm surge ranges to make it an entirely wind related scale that is now called the Saffir-Simpson Hurricane Wind Scale that began to be used in mid-May 2010. The storm surge portion is now technologically calculated through a computerized numerical model from the National Weather Service.

Because the wind portion of the Saffir-Simpson Scale is the only portion that remains in the Category modeling, laymen and citizens are less likely to understand the potential danger and damage that a storm can produce. The simplicity has been lost and therefore the public has become more complacent with their understanding of hurricanes, tropical storms and their potential impacts. Hurricane Harvey was a prime example of complacency on the part of the public.

When the storm intensified rapidly in the western Gulf of Mexico, the rain factor, producing more than 40 inches of rain, became the greatest threat. Harvey is the largest rain related hurricane in U. S. history and impacted an area that had been suffering 12 year drought conditions. These two facts combined left people stranded, clinging to their roofs, riding on top of their vehicles and worse. The Houston area will long remember the retired name Harvey and the rain and flooding that saturated downtown and surrounding communities.

What part of the hurricane is the most dangerous?

The eye of the storm, being the center is the calmest as it is clear and weather could be bright and sunny. The right side of a hurricane can be the most deadly. The right side of a hurricane contains the strongest winds due to the counter-clockwise motion of the storm. The right side tends to have 10-20 mph winds greater than the storm itself. Visit NOAA for a pictorial explanation of this phenomenon.

Wind, rain, storm surge, all of these combine forces to impact land. Are you prepared for the force? A simple rain storm with high wind can cause almost as much wind damage as a hurricane. Either case, know what is coming and how dangerous it can be. For more on hurricanes visit the Students page at NASA