Another year has flown by in a blur, which means that Hurricane Season 2011 is about to get underway. The hurricane season in the Pacific started back on May 15th, which forecasters say will be "timid," and the Atlantic hurricane season starts the Wednesday after next.
NOAA and others predict that this year's hurricane season will be extremely active, with quite a few storms expected. NOAA expects 12-18 named storms, 6-10 hurricanes, and 3-6 major hurricanes. The folks over at Colorado State (Caution: link is PDF) forecast 16 named storms, 9 hurricanes, 5 major hurricanes.
This season has the potential to replicate last year in terms of activity, last year having 21 systems, 19 named storms, 12 hurricanes and 5 major hurricanes. For a recap of last year's hurricane season, check out this diary I wrote last December.
Below is a repost of my preparedness diary from last May, with a few edits and add-ins. If you have any more information to add, please post it.
What are they talking about?
Chances are that if you listen to any news or weather network, you've heard them throw around different terms for storms. Hurricanes, tropical storms, subtropical storms, tropical depressions, Category 1-5 and so on. What's the difference?
Well, let's start from the bottom and work our way to the top. Keep in mind that the National Hurricane Center usually rounds the wind speeds to the nearest 0 or 5 (if a hurricane has winds of 122 MPH, it is reported to have winds of 120 MPH), so the numbers I list here may be different from what you're used to.
A Tropical DEPRESSION is a with winds less than 39 MPH...reported as having 35 MPH winds.
A Tropical STORM is a storm with winds between 39 and 74 MPH...reported as having between 40 and 70 MPH winds.
A HURRICANE has winds of 74MPH or greater...reported as having 75 MPH winds or greater.
With hurricanes, we use the Saffir-Simpson Scale to measure the wind speeds and the damage they cause. Categories 3, 4 and 5 are considered major hurricanes because their wind speeds can and will cause extensive damage upon landfall. Click the link for a very detailed description of what the scale means. Please keep in mind that the Saffir-Simpson Scale is only a measure of a hurricane's wind speed. It does not take into account storm surge, rainfall or the threat of tornadoes.
(Table created by me, source)
Another thing to keep in mind with the Saffir-Simpson Scale is that there is little difference between a strong Category 2 hurricane and a weak Category 3 hurricane. Don't judge a storm based on its title or category, as many Texans found out with Tropical Storm Allison in 2002, and as the entire country found out with Hurricane Katrina in 2005...which was only a Category 3 upon landfall.
When do they occur?
In North America, we have two hurricane seasons -- one for the Atlantic Ocean and one for the Pacific Ocean. The Pacific Hurricane Season begins first on May 15th and lasts through November 30th. The Atlantic Hurricane Season begins on June 1st and lasts through November 30th.
The peak of Pacific Hurricane Season occurs in early October, while the peak of Atlantic Hurricane Season occurs in mid-September (statistically falling on September 10th) and slowly drops off from there.
Where do they occur?
The location where tropical systems form differs from month to month. Click here for a detailed look at where storms are likely to occur in the Atlantic Ocean, broken down by months.
Here is a graphic showing the path of every known tropical depression, tropical storm and hurricane since records were kept in 1885.
(Source-- Click the image for an incredibly large, 53 MB graphic detailing the paths)
What are the threats involved?
Some of the threats involved in a hurricane, aside from the obvious wind hazard, are flooding, storm surges and tornadoes.
Flooding -- Flooding is a major problem in hurricanes. They can drop anywhere between a few inches of rain to upwards of 20-30 inches of rain, depending on how intense they are and how quickly they're moving. Even if you don't live directly on the coast, if you're in the path of a hurricane and you're in a flood prone area, it's best to leave if told to do so (or even if you think you're at risk).
Storm surge -- We all know how devastating storm surges are thanks to Hurricane Katrina. A storm surge occurs when the winds from a hurricane pile up water against the coast. Think of it like this: fill up a bowl full of water or soup. Blow along the top of the liquid. What happens? It ripples and pools up on the opposite end of the bowl in the direction you're blowing. It's the same principle...the water piles up along the shore and has nowhere to go but inland. The surge can be anywhere from a few feet deep to almost 40 feet deep, as we saw in Katrina. Flooding and storm surges are the deadliest parts of hurricanes, and sadly, the threats that people ignore the most.
Tornadoes -- Tornadoes are a hazard in the right-front quadrant of a hurricane. The right front quadrant of the storm is relative to its motion. If a hurricane is moving due west, the right front quadrant of that storm is the top left part on satellite (the NW part). Tornadoes can exacerbate the damage caused by flooding and winds in a hurricane, and need to be taken just as seriously as the storm itself.
What can I do to prepare?
For this, I will defer to the experts. The following is from the NOAA Hurricane Preparedness website, and the links follow to pages therein.
DEVELOP A FAMILY PLAN - Your family's plan should be based on your vulnerability to the Hurricane Hazards. You should keep a written plan and share your plan with other friends or family.Where can I go for more information?
CREATE A DISASTER SUPPLY KIT - There are certain items you need to have regardless of where you ride out a hurricane. The disaster supply kit is a useful tool when you evacuate as well as making you as safe as possible in your home.
SECURE YOUR HOME - There are things that you can do to make your home more secure and able to withstand stronger storms.
ONLINE VULNERABILITY INFO - There are web sites that can give you information about your communities vulnerability to specific hazards. These include hurricanes as well as other weather related hazards.
Good question. I have a linkapalooza for you...