Storm Update #3

Hurricane Gustav passed over us the night between Friday and Saturday. I awoke just after midnight to the sound of winds howling. It was some very substantial winds, but I am guessing the sustained wind force was no more than 70-80 km/h, with gusts significantly above that (say 100 – 120 km/h). The palm trees were clearly taking a beating with their crowns flying in a ball with tail formation. Below is a satellite image showing Gustav passing over the Cayman Islands.

Only casualty in our complex was a snapped tree trunk. At the height of the storm we lost power in our area. According to one eyewitness there was a massive blue flash of lighting behind one of the buildings in our complex around midnight.

In the morning we were still without power. But the winds had died down considerably. For those of you familiar stormy weather in Denmark, it was like a warm version of a rough and gusty winter storm. By the time we had done some wave watching and beach combing to keep the kids occupied, the electricity company had managed to restore electricity and life was pretty much back to normal.

We were lucky on Grand Cayman avoiding the grunt of Gustav. The sister islands: Cayman Brac and Little Cayman were not as lucky and appear to have suffered more damage. Below is a picture of a fallen power pole.

However, the hurricane season is far from over. The Atlantic seems to be brewing more storms for the Caribbean region and the National Hurricane Centre in Miami is monitoring other weather systems moving westward from the African coast. Ike has a good chance of becoming a large hurricane showing a large and very intimidating circulation, with plenty of heavy thunderstorm activity. While Ike’s sister, Josephine (AKA 99L), looks likely to form just off the coast of Africa on Tuesday.

UPDATE: Below is a image showing all four tropical weather systems currently in our waters. Starting to the far left is the remainder of Gustav (TD), then we have Hanna (TS) close to Cuba followed by Ike (TS) and finally Josephine (TD).

Storm Update #2

Forecasts today have substantially changed. Apparently, the ridge of high pressure that was forcing Gustav to the west shifted positions and caused Gustav to dip southwest. The center of Gustav is now passing Jamaica, and predictions strongly suggest Grand Cayman will be hit. The latest predicted path (including IR cloud coverage) is shown below. Note that another tropical storm Hanna has developed to the north.For the moment we can hope that dry air to the north and mountainous Jamaica will inhibit Gustav’s development. Late Friday, early Saturday is currently the best prediction of a hit on Cayman, if Gustav indeed hits us at all. I for one have become a bit skeptical of these computer simulations that are constantly being updated. Obviously when a weather expert tells you that a hurricane is heading your way, it's a good idea to prepare for impact or get out of the way, even if the storm ends up turning. But the erratic behaviour of Gustav so far makes me less pessimistic on Cayman’s behalf.

Btw, our office closes early today and will remain closed Friday. We are well prepared with lots of food and water and hurricane shutters on our windows. Stores remain open and although they are slightly more busy at times, there is no panic. We have been told electricity will remain on as long as possible, while the Water Authority will turn off the water supply at some stage to prevent potential damage to the distribution network. At this stage the weather remains fairly good. It is blowing more than usual, but the sun is still shining.

Storm Update

As many of you probably already know tropical storm / hurricane Gustav is approaching. Computer simulations suggest it might very well pass over the Cayman Islands. It is currently over Haiti and appears to be moving slowly westward towards Cuba.
The latest computer simulations are shown below.
Jeff Masters’ Wunderblog is not optimistic on Cayman’s behalf.

I think it is plausible that Gustav could intensify further, to Category 4 strength, before hitting the Caymans. If you have plans to be on the northern Cayman Islands--Cayman Brac or Little Cayman Island--on Friday, be prepared to be stuck there for several days, as Gustav may heavily damage these islands. Grand Cayman Island is also at risk--the GFDL model predicts Gustav will pass very close to Grand Cayman on Friday afternoon.

We are fairly well prepared, but Majken and Christoffer are doing some final shopping this morning to gather the final pieces. Shopping is a lengthy endeavour as all people scramble to prepare for the hurricane.

Hazards

The other day at work a colleague mentioned in passing the possibility of earthquakes here in the Caymans. What ?!! was my reaction. But he asserted me we live in an area prone to volcanic activity. That made me ponder what kind natural hazards I was exposing myself and my family to, by living in this region of the world. Based on a look at various websites, I came up with the following four major hazards: earthquakes, volcanoes, tsunamis and hurricanes.

Earthquakes, volcanoes and tsunamis enjoy a common father: the movement of tectonic plates. Grand Cayman lies on the plate boundary between the North American and Caribbean plates (see image), next to the Cayman Trough (or Trench).

The tectonic plates in Cayman’s region are in continuous lateral movement against each other, with the Caribbean plate traveling east at approx. 20 mm a year. The lateral movement limits the size of earthquakes in this area. However, in December 2004 a quake of 6.8 magnitude rocked Grand Cayman - there was no major damage though.

The following image shows the Cayman Trough together with an indication of Caribbean plate boundaries. The Trough has a maximum depth of 7,686 meters.

The depth of the Trough is more easily seen in the image below. It provides a perspective view of the sea floor of the Atlantic Ocean and the Caribbean Sea. Florida is on the upper right. The purple sea floor at the bottom center of the view is the Puerto Rico trench, the deepest part of the Atlantic Ocean. At the top of the image and to the left of Cuba you can see the Cayman Trench and what looks like small mountains. The top of the mountains are the Cayman islands - the realisation that we are on top of massive underwater mountains in the middle of nowhere made me feel small and vulnerable.

Along the northern east part of the Caribbean plate, including areas in the vicinity of Jamaica and the Virgin Islands, moderate earthquakes of shallow depth are generated. In the Eastern Caribbean seismic events are common and principally associated with a subduction zone at the junction of the Caribbean Plate and the North American Plate. The North American Plate slides underneath the Caribbean Plate along a north-south line just east of the arc of Caribbean islands.

Several of the islands of the Eastern Caribbean are volcanic in origin. Grenada even has a submarine volcano called Kick 'em Jenny. Studies dating back to 1972 indicate that minor eruptions have been occurring on a fairly regular basis and that the summit of the volcano is growing at a rate of approximately 4 metres per annum.

To conclude, on a hazard rating of 1 to 10 for Cayman: volcanoes = 0, earthquakes = 2.

So what about the possibility of a tsunami? The majority of tsunamis are related to tectonic displacements associated with earthquakes at plate boundaries. However, tsunamis can also be generated by erupting volcanos, landslides or underwater explosions (and meteorites). For islands in the vicinity of Kick’em Jenny that is bad news.

Grand Cayman has large boulders on its south coast that geologists believe were moved from the seabed to land by a tsunami. Carbon-dating of dead sea-plants on the rocks put the event in 1662 plus-or-minus 25 years. That time-period comes close to including the 1692 earthquake and the event-generated tsunami and landslide that killed over 2,000 in Port Royal, Jamaica. However geologists believe that Grand Cayman's rocks were moved by an even greater event.

For us in the Cayman, I doubt tsunamis pose a significant threat. It seems to me that possible movements in the Cayman trench are at a depth and of a type (horizontal not vertical movement) that would be unlikely to create a tsunami. My hazard rating: tsunami = 1.

Finally, we have hurricanes which name is derived from the Mayan storm god Hunraken and the Arawak (Amerindians encountered by the Spanish explorers) word hurican, which meant the devil wind. As I noted in a previous post one of the greatest of all recorded hurricanes occurred in October 1780. Nearly 20,000 people perished. Warmer waters also increase their intensity.

Here in Grand Cayman, hurricane Ivan (two years ago) caused massive damage. Damage which is still evident today. Apart from strong winds and flying debris, one of the major contributors to damage was the surge of water, flooding almost all parts of the low-lying island. I would say the likelihood a direct hit by a hurricane is substantial. My hazard rating: hurricane = 8.

Writing about hurricanes reminds me of an article I read in the local newspaper a few weeks ago. It was on the (economic) cost of hurricanes. It is pretty obvious that people who live in hurricane prone areas must expect to incur additional costs to protect themselves. Building construction needs to be of a higher grade, insurance is more expensive, etc. However, one thing I had not thought about (which in retrospect seems obvious) is the cost to businesses of having emergency hurricane disaster plans in place and the cost of acting upon these plans in the event of a possible hurricane event. Think of staff evacuation, additional back-up options for data, standby office space off shore etc. When hurricane Dean passed south of Cayman with no consequence whatsoever a month ago, most firms engaged their pre-hurricane disaster plans. While some incurred little cost, some sent all staff off island at considerable expense.

Storm of 1780

I am currently reading a book on the history of the Caribbean. To follow-up from the previous post where I briefly mentioned hurricanes, there is an account in the book of a hurricane that passed over the region in October 1780. During its passage, it killed well over 22,000 people and totally destroyed large British and French naval fleets as well as hundreds of merchant ships. Back then there were no instruments to measure the force of the hurricane, but maximum wind gusts are thought have exceeded 300 km per hour since raindrops stripped the trees of their bark!

Back in the Caymans

I am back in the Caymans, having accepted the job offer from the Information, Communications and Technology Authority (ICTA). I have been given a week to sought out all tasks related to a move abroad: accommodation, schools, banking etc. So far I have opened a bank account and found a place to live. The apartment is located in the George Town area close to schools and work. It has a sea view and direct access to the sea and a beach half a block away. The Google Earth coordinates are: lat=19.2784135251, lon=-81.3917586815

As I write this post there is a thunder storm passing overhead. The last couple of days I have been watching the developments of hurricane Felix. It passed way south of Cayman as expected. The people here didn’t make any fuss at all. With hurricane Dean a few weeks ago, however, it is my understanding that some areas were vacated and people prepared themselves for a hit.

The potential for a hurricane passing over the Caymans has influenced me in some of my tasks this week. For example, when renting a house, a two story is recommended. During hurricane Ivan (three years ago), the island was nearly covered in sea water. A quarter or more of the buildings on the islands were reported to be uninhabitable, with 85% damaged to some extent. A second story can keep you dry. Another example, is my choice of car. During Ivan almost all cars were covered in sea water, ruining car engines. Obviously, I don’t intend to buy an amphibious vehicle, but through private purchase there is a risk of buying an Ivan infected car. As a person with very little understanding of car mechanics, this has narrowed my car search efforts to car dealers.

The prospects of a hurricane passing over the island both scares and fascinates me. Currently, we in the midst of the Atlantic hurricane season. The figure below illustrates the Atlantic hurricane season with over 97% of tropical activity within the period of 1 June to 30 November.
There is evidence that the global warming might be making the storms stronger (not increasing their number). In addition, global warming may also be causing sea levels to rise. The Northwest Passage is now open (connecting the Atlantic and Pacific Oceans) and melting polar ice and glaciers may cause a rise in global sea levels - something that should be a major concern for Caymanians. Cayman Islands is very low lying and I suspect a rise of only a few meters could have disastrous effects.