WORLD METEOROLOGICAL ORGANIZATION___________________________________________

RA IV HURRICANE COMMITTEE

FORTIETH SESSION

FORT-DE-FRANCE, MARTINIQUE, FRANCE

9 to 13 APRIL 2018

RA IV/HC-40/Doc 3.2(9)(20.I.2018)________

ITEM: 3.2

Original: ENGLISH

REVIEW OF THE PAST HURRICANE SEASON

Reports of hurricanes, tropical storms, tropical disturbances and relatedflooding during 2017

Report from the British Caribbean Territories

(Submitted by the British Caribbean Territories)

RA IV/HC-40/Doc 3.2(9), p. 2

1. Introduction

The British Caribbean Territories were particularly hard hit by the 2017 Hurricane Season. Hurricane Irma impacted on Anguilla, the British Virgin Islands and the Turks and Caicos Islands, while Hurricane Maria added to the woes in the Turks and Caicos Islands.

2. Hurricane Irma

The centre of Hurricane Irma passed within 7.5 miles (12km) of the nearest point of the southwestern tip of Anguilla on the morning of 6 September and Figure 1 shows that Anguilla experienced the effects of the passage of the eyewall.

Figure 1: Satellite image showing the proximity of the centre of Irma to Anguilla.

Data was retrieved from an automatic weather station located at the Clayton J. Lloyd International Airport in Anguilla, at latitude 18°12'20.20"N and longitude 63°03'15.23"W at a height of 30 meters above mean sea level. This showed that between 0630UTC to 1600UTC, 345.8 mm of rainfall was measured with the highest 10 minute totals occurring between 1040UTC to 1120UTC. Figure 2 is a graph of the 10 minute rainfall for the time period mentioned above.

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Figure 2: 10-minute rainfall totals in millimeters.

RA IV/HC-40/Doc 3.2(9), p. 3

Although the center of Irma did not pass over Anguilla, the island recorded a 10-minute average wind speed of 165.4kt at 1400UTC. Figure 3 shows the average 10-minute for the period 0630UTC to 1600UTC. The lowest barometric pressure measured as shown in Figure 4.

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Figure 3: 10-minute average wind speed

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Figure 4: Barometric pressure as read by the AWS

RA IV/HC-40/Doc 3.2(9), p. 4

The damage caused by Irma in Anguilla was extensive; the southern and western sides of the islands suffered the worst of the damage. The island lost electrical power because of damage to the infrastructure, approximately 98% of the housing stock was damaged, and there was one death. The Government of Anguilla estimated that the total cost of physical damage was USD 290 million. Figure 5, shows some of the damage which occurred in Anguilla.

Remnants of a Sutron AWS at the Airport Damaged aircraft

Methodist Church Vehicle in Airport parking lotFigure 5: Some images of the damage inflicted by Irma on Anguilla.

The centre of Irma then passed over Beef Island in the British Virgin Islands just after 1700UTC on 6 September with winds forecast to be 161kt (185mph). However, the highest wind speed measured by the automatic weather stations managed by the Department of Disaster Management was 90kt (103mph) measured at Brewers Bay (18°26'36.04"N, 64°38'49.00"W) during the passage of the centre of Irma over Beef Island before the AWSs were destroyed.

The winds and the seas were so ferocious that yachts which were moored in the enclosed Paraquita Baywith only one egress channel on Tortola were transported to Virgin Gorda approximately 9 miles (15km) to the east-northeast. Figure 6, shows the difference in Paraquita Bay after the passage of Irma. Further, vehicles which were washed away from Tortola were found on cliffs on other islands and small aircrafts were ripped from their hangers and deposited on buildings some 100 feet away from the hangers.

RA IV/HC-40/Doc 3.2(9), p. 5

The Government indicated that Irma caused injury to 125 persons and there were 6 deaths. The Islands which has a tourism-based economy, lost 65% of its hotel stock and a further 25% were partially damaged and 85% of the yachting industry was destroyed. The estimated cost of the damage to the British Virgin Islands was USD 3.6 billion.

Before Irma After IrmaFigure 6: Before and after images of Paraquita Bay, Tortola after the passage of Hurricane Irma

After Irma devastated the British Virgin Islands on 6 September, it approached the Turks and Caicos Islands on 7 September. The Turks and Caicos Islands make up a small archipelago just to the north of Hispaniola, as shown in Figure 7.

Figure 7: The islands of the Turks and Caicos Islands

At its closest, the center of Hurricane Irma reached within 25 miles (40km) to the closest island as a category 5 hurricane, with forecast winds initially of 152kt (175mph) but it was forecasted to decrease to 143kt (165mph) as it closed on West Caicos. There is no meteorological observational data associated with the passage of Irma, but the damages estimates suggest that the archipelago received at least category 3 hurricane force winds.

RA IV/HC-40/Doc 3.2(9), p. 6

Although there were no deaths associated with Irma as it passed to the south of the Turks and Caicos Islands, there was damage to at least 65% of all the buildings. The easternmost islands of Salt Cay, Grand Turk and South Caicos had extensive damage and a state of emergency was declared for those islands. There was massive flooding especially in Providenciales, the most populated island, which disrupted international air travel as shown in Figure 8.

Providenciales International Airport Toppled communication mast

Roof loss (Providenciales) Roof loss (Grand Turk)Figure 8: Images of some of the damage in the Turks and Caicos Islands

3. Hurricane Maria

Hurricane Maria approached the Turks and Caicos on 22 September after causing catastrophic damage during the passage of its center over Puerto Rico. The center of Maria passed within 55 kilometers of the east coast of Grand Turk and caused further damage to Grand Turk, Salt Cay and South Caicos; but in relation to the damage caused by Irma, Maria's damage was not easy to ascertain.

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