Preparation is key defence against storm force winds

As we approach the season of destructive weather Mike Compton looks at the latest preventative measures to avoid major damage

It is a feature of the patterns that drive the world’s weather that virtually at any time of the year, there is a high possibility of storm force winds for at least one area of the world. So it is that by the time this column is being read, a substantial part of the globe is heading for that time of the year when such winds can be expected. They may be given different titles, such as cyclones, typhoons or hurricanes, and be personalised by being given differing individual names, but the effects are the same and they can be devastating.

In 2006, the TT Club published a very helpful document on this subject called WindStorm. A revised and greatly expanded second edition has just been issued, this time as a joint publication with ICHCA International*.

Since 2006 there have been many more severe high winds that have impacted spectacularly on ports and port facilities and the new edition includes a variety of such experiences over a range of time. These stories, which came from many regions of the world and had a variety of outcomes, include preparation, storm effects and the aftermath. The Beaufort Scale, the generally accepted method of measuring the size of a wind and also its effects, starts at 0 for "calm" and goes up to 11 for "violent storm" and 12 for "hurricane".

It also extends to 17 to show the various degrees of strength of hurricanes and the Saffir-Simpson Scale numbers these extra five categories as 1-5 to show the extent and strength of such tropical cyclones. If a hurricane is said to be category 1, therefore, which is the lowest, that is still equivalent to Beaufort Scale 13 and will be a significant event. However, a storm with a category of 5 can cause complete roof failures, for example. As such storms bring with them a considerable storm surge of the ocean surface, it can also cause flooding to a considerable degree. With their proximity to the sea, ports and terminals are especially vulnerable. Whether they are side-swiped by a storm passing up the coast, hit by the outer edges of a storm as it comes ashore or hit full on by such a landfall, considerable damage to port and terminal facilities can result and the potential for injury is always present.

The second edition of WindStorm is, therefore, particularly helpful as it is packed with information regarding preventative actions ports and terminals can take to mitigate against the worst effects that might be felt as well as how to recover afterwards.

As an example of what a storm can do, the eye of hurricane Hugo as it travelled across the port of Charleston in 1989 not only removed all the navigational aids within the harbour area but also moved the ship channel. As a consequence, the channel had to be resurveyed and marked before shipping could enter the port again.

The most vulnerable part of a terminal has to be its cranes and other lifting appliances as their wind profile is greater. A number of incidents are quoted and a substantial new element of this second edition is the extensive advice given on tie-down arrangements.

In this regard, it is noticeable that the matching of a crane and its built-in tie-down provisions to the terminal’s own anchoring arrangements is sometimes found to be the weak link and which, as a result, fails under the stress of a severe storm.

One of the most important elements in considering the possible onset of such storms is to formulate an emergency plan and there is much detail on what this should include. A crucial element is to be linked to a reliable weather forecasting service, especially one that can give information and advice on a local basis.

Hugo was anticipated and the new edition of WindStorm lists the precautions that were taken prior to the storm hitting, the clear up undertaken afterwards and the lessons that were learnt. If there is enough warning, many steps — some of them quite simple actions — can be taken which will at the very least minimise the effects. Many experiences, each with a lesson to be learnt, are quoted. One collision between two specialised cranes had the ultimate effect of causing a very efficient shipping company to go out of business. The immediate incident was occasioned by one crane not being secured before a high wind appeared. They were the only two cranes and, through a set of circumstances that could only be described as highly unusual, the failure to take a simple precaution caused the collapse of the business.

Fortunately, most are not as severe but it is very clear that the effects can still be devastating and this new booklet will be of great interest to all those terminals that may be affected. cs

*WindStorm, edition 2 is available for GBP £36 from the TT Club at www.ttclub.com under publications or at www.ichca.com.