Monday, September 25, 2017

#HurricaneMaria hits Guadeloupe,US Virgin islands, Puerto Rico, Dominica

Dear reader,

just as hurricanes Harvey and Irma left Texas & some parts of the Caribbean in  ruins, another hurricane - Maria - wreaked havoc in some parts of the Caribbean which haven't been punished that much a few days.

Regarding communications and electricity supply at least two islands - St. Croix and Puerto Rico - have been hit by Maria. Although the hurricane went through an eyewall replacement circle just before hitting Puerto Rico with "just" category 4, St. Croix was hit when it still was a category 5 storm. The effects on the islands' infrastructure was quite similar - In Puerto Rico according to initial reports from various sources 100% loss of the power grid & a 95% loss of cell towers for mobile phone voice and data connections.

Ricardo Rossello, and officials still had not had communication with nine of 78 municipalities.
"This is a major disaster," he said. "We've had extensive damage. This is going to take some time."


Besides the loss of electricity the subsidiary of the US National Weather Service lost its radar, which was also blown off its mast. The island which has about 3.5 million inhabitants is plunged almost completely into darkness and the fresh water supply is also affected. Many hospitals have been rendered useless, because of destruction or because vital supplies needed for running a hospital can't get delivered. Officials from Puerto Rico indicated that the electricity situation could last the next 4-6 months.

Roads access to many places has been restored, but gasoline & diesel (¹) is rationed and this affects also the generator operations resulting in frequent loss of local communications which could be restored. From US Virgin Islands reports are being picked up, which seem to suggest that cell towers running on generators are forced off the air because the generators are getting stolen.

People from outside Puerto Rico e.g. from the US mainland are desperately trying to get in touch with their relatives and because the Internet is also heavily affected the usual helpful tools like people finders by e.g. the Red Cross or by Google can't be used.

The most catastrophic scenario regarding communications and electricity has happened including "back to the basics" which is in this case to rely on ham radio operators and their shortwave transceivers. Initial reports however suggest that some operators also have problems with their generators, since gas stations are far away and are only supplying private citizens with a few liters of gasoline or diesel fuel.

Contrary to the earthquake event which occurred in Mexico and which claimed so far 300+ lives, the loss of life - at least as of known today- is fortunately low. Since the measures to restore communication and electricity have been described here just a few days ago (regarding hurricane Irma) this blog post will show some damage inflicted on transmission towers, cell towers, antennas, dishes, electricity poles, sub-station, transformers, etc. There will be also some tweets on the fuel scarcity currently in Puerto Rico, which impacts also the use of generators.

Some photos will be added in the upcoming hours as well as some indications of some backup communications already implemented. (by the military and radio amateurs)

Stay tuned ...

Impact on communication & electricity infrastructure 
(various islands, various sources,tweets currently unsorted)





























So it's fair to conclude that all structures carrying cables or antennas have failed on those islands subjected to cat4/5 hurricane winds. Estimates during hurricane Irma's period of being a category 5 storm: approximately as devastating as a F3-F4 tornado ! All masts and poles, not just the (local) wooden ones, have been either totally destroyed (complete structural failure/collapse) or did at least bent enough to allow cables to break. It's also fair to assume that no tests were conducted on all those types of masts and utility poles and the ones used were just "normal" ones which can used in 'dead calm areas'. From own experience with antenna masts and attached UHF/VHF aerials it can be concluded that the torque what impacts the bending moment of the mast is often underestimated. Attached items like antennas or cables and insulators produce additional stress (wind load) to certain points of the structure and forcing the material to either bend or break.

Since antennas for either cell services or TV and radio broadcasts have to be installed on a elevated position those masts have to be considerably stronger than ones currently in use (or destroyed on those affected islands). Wooden structures have been blown to pieces (also roofs and trees) so this material can be deemed not strong enough to withstand 250-300 km/h winds. Masts made of steel or concrete must get reinforced, perhaps by adding additional materials or by simply enhancing the thickness/density of the materials used. The manufacture's guidelines for additional attachments to this structure must also be followed by those telecom firms which use them. If it turns after testing that those structures can't be made strong enough to withstand such winds, at least oblige those firms to have sufficient spare parts in place to restore services withing hours or days, not weeks or months ! 

Electricity cables however are installed above the ground because it's cheaper, not because it's technically impossible to implement other solutions. Serious questions have to be asked why many countries in Europe, which don't even suffer from such kind of destructive winds, are used to lay cables in the ground. It's not only possible for rather low voltage lines which are directly connected to people's homes, but also highest voltage cables for underground or seabed installation are available. Of course it's more work and more expensive to have them installed beneath the earth's surface, but in such hurricane prone areas the damage to public and private property and even the risk of costing lives is too high. Utilities have to be forced to overhaul their entire network within a reasonable time frame, not only including underground cables, but also 'circuit breakers' like large capacity battery systems at least nearby buildings with extreme importance for upholding public safety.
 
failing power & communication infrastructure during previous tropical cyclones:
Power out in parts of Yolanda-hit Tacloban City [PHL, GMA news, Dec 28 2013]
Leyte and Samar islands still without power days after Yolanda super typhoon [PHL, GMA news, Nov 13 2013]

related reading:
(please note: EZR endorses this message in general, but not necessarily the use of (certain) words) 
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