Hurricanes

Hurricanes are not caused by global warming according to the insurance industry, which insists they are "Acts of God."

Hurricane Facts

We are not seeing major hurricane increases due to global warming or any other reason. The last major hurricane (defined as a Category 3 or above) to hit the US mainland was  Hurricane Wilma, which made landfall in Florida on Oct. 24, 2005.

Although a major hurricane typically strikes the US about once every two years, no major hurricanes have made landfall in the US for more than 10 years.

The second longest stretch between major hurricane strikes was between the major hurricane that struck in August 1860 and the one that struck in September 1869, NOAA records show. The third longest stretch was between the major hurricane that struck in September 1900 and the one that struck in October 1906.

Hurricanes

The last major hurricane (defined as a Category 3 or above) to hit the U.S. mainland was  Hurricane Wilma, which made landfall in Florida on Oct. 24, 2005.

Although a major hurricane typically strikes the U.S. about once every two years, no major hurricanes have made landfall in the U.S. for more than ten years.



The second longest stretch between major hurricane strikes was between the major hurricane that struck in August 1860 and the one that struck in September 1869, NOAA records show. The third longest stretch was between the major hurricane that struck in September 1900 and one that struck in October 1906.

What Causes Tornadoes

The first four months of the year brings risk for tornadoes in the southern US. From April through June, the biggest tornado threat shifts to the Plains, Upper Midwest, and Great Lakes. The main tornado risk then stays along the northern tier of the country through much of summer, while tropical storms and hurricanes increase back in the South as they move inland. These are followed in November and December with more chances of tornadoes moving back to the South.

About ninety percent of US twisters occur in a 300-mile wide corridor extending from West Texas to Canada. Warm, moist surface winds blow up from the Gulf of Mexico, while cool high-altitude winds blow over the tops of the Rockies. The cool air wants to sink while warm air wants to rise. However, the mountain air causes a temperature inversion, which prevents the warm surface air from rising. It is like clamping the lid on a pressure cooker. The surface weather systems build up a big head of steam until they break through the inversion and shoot up to towering heights and the violent updrafts and downdrafts lead to form tornadoes. Tornadoes occur most frequently in the central plains of the US. Australia has the second most tornadoes each year.

Hurricanes and Storms

Umbrellas do not provide protection from hurricanes and storms. During the rainy season we also have many types of storms. The word “hurricane” is thought to have come from the Mayan name for the god of storms “Hurukan”.

When a storm has wind speeds of 38 mph it is called a tropical depression. It is called a tropical storm if it has wind speeds between 39-73 mph. Above 74 mph it is called a hurricane. Anything above 111 mph is known as a major hurricane.

Hurricanes are classified differently depending on what country you live in. In the United States, typically the Saffir-Simpson Hurricane Wind Scale is used, classifying the hurricanes from Category 1 through Category 5, based on their sustained wind speeds. This scale was developed by Herbert Saffir and Bob Simpson, in 1971.

Saffir developed the scale trying to estimate the amount of property damage a specific hurricane would do, primarily looking at damage the wind would do to structures. Simpson added flood damage. What they came up with is the following table:

    Category 1: 74-95 mph
    Category 2: 96-110 mph
    Category 3: 111-129 mph
    Category 4: 130-156 mph
    Category 5: 157 mph and up