Forget the economic news, the fighting in Libya, and the American Idol summer tour and pay attention to the weather report.

Hurricane Irene is wending its way across the Caribbean and heading for the East Coast of the United States, where it may make landfall along the Carolinas. When the storm reaches the U.S., it may reach Category 4—that’s a serious storm. The definition of Category 4 is: “Catastrophic damage will occur.”

Before the storm hits, it is worth revisiting the danger Americans may face. A hurricane is a particularly powerful weather event. Hurricanes result from low-pressure conditions occurring in tropical waters, which in turn produce rotating winds. Besides generating high winds and intense rains, hurricanes push the surface ocean in their path. The wall of water in front of a storm can be over 20 feet in height and hundreds of miles wide. This bulge of water can produce a “storm surge” when it reaches coastal lands, resulting in significant floods. Hurricanes can also spawn tornadoes.

Hurricanes can span 400 miles or more in diameter and last up to 12 days, though the average “life” of a storm is nine days. The storms move along a path influenced by a number of factors, taking them in a direction that remains at sea or makes landfall. Their paths are not entirely predictable and are known to shift significantly. The average speed of a hurricane is 15 miles per hour, though the wind speeds within the storm itself can range from 74 to more than 155 miles per hour.

Storms are categorized on the Saffir–Simpson Hurricane Wind scale from 1 through 5. Each category represents a range of sustained wind speeds and the estimated damage they would cause. Here is how the scale describes Category 4:

There is a very high risk of injury or death to people, livestock, and pets due to flying and falling debris. Nearly all older (pre-1994) mobile homes will be destroyed. A high percentage of newer mobile homes also will be destroyed. Poorly constructed homes can sustain complete collapse of all walls as well as the loss of the roof structure. Well-built homes also can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Extensive damage to roof coverings, windows, and doors will occur. Large amounts of windborne debris will be lofted into the air. Windborne debris damage will break most unprotected windows and penetrate some protected windows. There will be a high percentage of structural damage to the top floors of apartment buildings. Steel frames in older industrial buildings can collapse. There will be a high percentage of collapse to older un-reinforced masonry buildings. Most windows will be blown out of high-rise buildings resulting in falling glass, which will pose a threat for days to weeks after the storm. Nearly all commercial signage, fences, and canopies will be destroyed. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Long-term water shortages will increase human suffering. Most of the area will be uninhabitable for weeks or months.

The National Hurricane Center provides up-to-date information on the path of these storms. The Federal Emergency Management Agency (FEMA) provides general guidance for what to do before, during, and after a hurricane. States also provide information on their emergency management Web sites. FEMA also provides an index with contact information on state agencies.

While we worry about the approach of Hurricane Irene, we also need to worry about FEMA. Today, The Heritage Foundation will release Homeland Security 4.0. The event will be covered live on the Heritage website and C-SPAN at 11 am (EST).

One of the key findings of the report is that FEMA has been increasingly distracted from preparing for large-scale disasters like Category 4 hurricanes. Heritage homeland security expert Matt Mayer points out that FEMA “has been responding to almost any natural disaster around the country, be it a contained three-county flood, or a catastrophe of near-epic proportions like Hurricane Katrina. As a result, many states and localities have trimmed their own emergency-response budgets, often leaving them ill prepared to handle even rain- or snowstorms without federal assistance. This leaves FEMA stretched far too thin and ill prepared to respond to grand-scale catastrophes.”