Many people are already wondering just how high the Saffir-Simpson wind scale goes – Will Irma become a Category 6 or even a Category 7 storm?
A Category 5 on the Saffir-Simpson hurricane scale has no upper limits, at least on paper. But many scientists say winds from a powerful hurricane could easily blow the scale right out of the water. The scale only estimates potential property damage. However, when a storm reaches Category 5 status, it doesn’t matter what you call it, it’s totally bad.
But keep in mind that Category 1 or 2 storms are still dangerous and preventive measures are still needed to protect property and lives. This is because other elements like storm surge, rainfall amounts, and wind damage are still relevant. In the western North Pacific, the term “super typhoon” is used for storms with winds over 150 mph.
The introduction of the wind scale to the public
Civil engineer Herbert Saffir and meteorologist Robert Simpson, with the NHC, introduced the Saffir-Simpson Hurricane Wind Scale to the public in 1973 because some sort of scale was needed for describing the likely wind effects from a hurricane.
They mirrored the Richter Earthquake Magnitude scale, with the hurricane wind scale using a 1–5 scale based on wind speed and its damaging effects, but also included storm surge, pressure and flooding effects.
In 2010, a new Saffir-Simpson scale became operational at the National Hurricane Center, focusing only on wind speed and the damage that can be anticipated. This means that a Category 2 storm hitting a city along the coast will cause a lot more wind damage than a Category 5 storm hitting a rural area.
Category 5 is the highest level a tropical cyclone can attain on the Saffir–Simpson scale. These storms cause complete roof failure on many residences and industrial buildings, as well as extensive damage to major infrastructure. Massive evacuation of residential areas may be required if the hurricane threatens populated areas.
Total and extremely long-lived extensive power outages and water losses are to be expected, possibly for up to several months. Hurricane Andrew (1992) is an example of a hurricane that brought Category 5 winds and impacts to coastal portions of Cutler Ridge, Florida with Category 4 conditions experienced elsewhere in south Miami-Dade County.
Looking at Hurricane Irma at 2:00 p.m. on Sept. 5
At 2:00 p.m. today, Hurricane Irma was about 180 miles (290 kilometers) East of Antigua and about 185 miles (295 kilometers) east-southeast of Barbuda, packing maximum sustained winds of 185 mph (295 kph), moving toward the West at 14 mph. The minimum central pressure is at 926 MB, 27.34 inches.
The storm’s forward motion is expected to continue today, followed by a turn toward the west-northwest tonight. On the forecast track, the extremely dangerous core of Irma is forecast to move over portions of the northern Leeward Islands tonight and early Wednesday.
The forecast notes that while some fluctuations in intensity may occur over the next several days, Irma will continue to remain a very powerful and dangerous Category 4 or 5 storm, with extremely dangerous storm surges and winds. Rainfall amounts totaling 8 to 12 inches are expected with isolated maximum amounts of 18 inches across the northern Leeward Islands. Puerto Rico is expected to get rainfall amounts of between 4 to 10 inches with isolated maximum amounts of 15 inches or more in the northeast.
