Weather Safety: When To Expect A Hurricane Evacuation

How experts determine where to issue hurricane evacuations and what types of things they look for.

Hurricanes can be very dangerous storms especially for those living right along the coast line. It is up to the authorities to examine the storm, predict the severity and landfall times and locations. While making these determinations, one thought is sitting at the backs of their minds. When and where will we have to utilize an evacuation plan? There are two main methods for determining the need for an evacuation.

The Decision Arc Method is a complex method. When a hurricane approaches the coastline on an acute angle, there is much room for error. The predicted place and time of landfall can greatly change with just a small movement in the path of the hurricane. This can cause the evacuation points to change as the storm approaches and this is also why some evacuations are done shortly before the storm actually hits. This method uses both the Decision Arc, which plots out the potential path of the hurricane based on its forward speed, and the STORM (Special Tool for Observing Range and Motion), which uses a two-dimensional diagram used to determine the radii of the storm.

This helps them to determine a crossing point, where, when the hurricane crosses this point, they will have to make their decision on where to evacuate. This crossing point is just far enough away to be able to evacuate everyone safely. Once the storm has crossed this point, it is too late to evacuate anyone else.



The other frequently used method is the HURREVAC computer program. This program takes a look at the storm and predicts the worse case scenario for that particular storm based on its strength and speed. It predicts a lot of information including when is the latest to evacuate, when will winds begin to blow in an area, and when the eye is expected to make landfall. The program puts out a full list of all evacuation possibilities for the authorities to choose from when the proper time comes.

Hurricane evacuation areas are generally evacuated in sections. The areas directly on the coastline in the predicted path of the hurricane are generally the first people told to leave. This decision is based on the strength of the storm and sometimes also on the expected duration of the storm. If the tides will be particularly high, the coastlines will also be evacuated. As the speed of the winds and the height of the predicted tides rise, the evacuation moves itself farther inland and farther up and down the coastline. Mobile homes are encouraged to evacuate if the hurricane is going to cross their area at all since these homes are less stable.

Deciding whether or not to evacuate is still a very personal decision, but is one that can cost you your life. If at all possible, those being asked to evacuate, should. But if you for some reason would choose not to, then precautions should be taken such as boarding up windows and stocking up on bottled water and non-perishable foods. Evacuations are issued for the safety of the local residents and should be taken seriously. The decision to evacuate is not made lightly. The authorities take a lot of time and put a lot of effort into making the correct decision and residents should respect that.

© High Speed Ventures 2011