RA IV/HC-40/Doc. 3.2(2), p.1

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(2)
(5.III.2018)
______
ITEM 3.2
Original: SPANISH

REVIEW OF THE PAST HURRICANE SEASON

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

Report from the Dominican Republic

(Submitted by the Dominican Republic)

1.Introduction

Owing to the forecast track of Hurricanes IrmaandMaría, the Government of the Dominican Republic had to activate the national emergency system. Although the centre of neither hurricane struck Dominican territory directly, the associated bad weather activity, such as heavy rainfall, strong winds and heavy seas particularly affected the eastern, north-eastern, central, northern and north-western parts of the country. The rest of the country experienced rainfall, but this was less intense and less frequent.

The centre of Hurricane Irma began to move inthe early hours of Thursday, 7September,and bymidnight on the same day it had reached the south-eastern Bahamas. Hurricane Maríamoved between the night of Wednesday, 20 September, brushing north-east Cabo Engaño,and the morning of Friday, 22 September, when it approached the southernmost tip of the Bahamas.

The alerts and warnings disseminated via the official bulletins of the National Meteorological Office(Oficina Nacional de Meteorología (ONAMET))were issued within the time frame established under regional and national protocols. It should be pointed out that in the case of Hurricane Irma, the early weather warning, which according to the national protocol should be issued between 60 and 72 hours prior to possible impact, had to be given 96 hours in advance. This was because it was a Sunday, which could have given rise to some delay in producing the press coverage for the following day, Monday.

2.Tracking of Hurricane Irmaand issuing of watches and warnings

At7 p.m. local time on Sunday, 3 September,the National Meteorological OfficeSpecialized Information Centre decided to issue an early weather warning, particularly for the coastal points from Cabo Engañoto Cabo Frances Viejo, so that coordination meetings between the civil protection bodies could begin. At that time, the centre of Hurricane Irmawas approximately 1,230 km east of the Leeward Islands.Irmamoved in a westerly direction at around 22 km/h,with maximum sustained winds of 185 km/h.

After some 36 hours, the early weather warning was changed to a hurricane watch on Tuesday, 5 September, at 7 a.m. local time: in coordination with the Regional Specialized Meteorological Centre, ahurricane watch was issuedfrom Cabo Engañoto Manzanillo Bay in the north, and a tropical storm watchwas issued from Cabo EngañotoSaona, including inland, eastern, north-eastern, northern and north-western regions of the Dominican Republic. At that time Irma was centred about 465 km east of the Leeward Islands and some 1,135 km east/south-eastof Cabo Engaño, at the eastern tip of the Dominican Republic.Irmacontinued to move in this direction, with maximum sustained winds of 240 km/h.

On the evening of Tuesday, 5 September, whenIrmawas around160 km east of Antigua and some 900 km east/south-east of Cabo Engaño, with estimated maximum sustained winds of 295 km/h, and hurricane winds and stormy winds extending 95 km and around 280 kmfrom its centre respectively, the National Meteorological Office again decided, in coordination with the Regional Specialized Meteorological Centre,to change the watchesto a hurricane warning fromCabo Engañoto Manzanillo Bay in the northern coastal sector andto a tropical storm warning from Cabo Engañoto Pedernales,along the entire southern coastal region, and throughout most of the inland regions of the country.

On the night of Wednesday, 6 September, while the warnings were still in effect, the centre of Irmawas located some 90 km north/north-westof San Juan, Puerto Rico and some 315 kmnorth-east of Cabo Engaño, with maximum sustained winds of 295 km/h and stronger gusts, moving west/north-west at around 26 km/h. At this point, associated cloud masses began to appear, owing to the circulation affecting the Mona Passage and the east of the country. The meteorological observatory at Punta Cana International Airport reported heavy rainfall.

In the early hours of Thursday, 7 September, when Irma was centred some 120 km north/north-eastof Cabo Engañowith maximum sustained winds of 290 km/hand its movement unchanged, localities such as Punta Cana, Samana, Miches and La Romana reported wind gusts of between 35 and 75 km/h, while moderate to intermittently heavy rainfall was recorded, particularly in eastern, north-eastern and northern parts of the country. In the following hours, after passing close to Cabo Engaño, it approached the north/north-eastof Cabo Cabron, Samana at some 95 km. Irma’swindspeedthen dropped to 285 km/has it moved away to a point some 160 km north of Cabo Engaño.

By midday, Irmahad not significantly changed, although the winds had weakened in intensity to 280 km/hat a point some 95 km north-east of Puerto Plata. The national network’s meteorological stations, as well as some collaborating bodies, continued to report wind gusts of between35 and 100 km/h. Similarly, conventional and some automatic stationsreported precipitation in excess of 65mm in the space of three hours. These included the stations of Los Montones:San José de Las Matasin theCibaoValley and Mao, which reported 87 mm and 80 mm respectively. Samanain the north-east of the country and Arroyo Barrilin the central region reported 150 mm and 93 mm respectively in 24hours.

In the afternoon of Thursday, 7 September, when Irmawas located some 105 km north/north-west of Puerto Plata andmaintaining the same movement, wind gusts of between 76 and 111 km/hwere reported at Las AméricasInternational Airport and Samana International Airport respectively. Accumulated rainfall continued to increase, exceeding 100 mm at some stations, most notably San José de Las Matas with 130 mm, 120 mm in GuiDom and 109 mm in La Barranquita, Santiago.Warnings were lifted in most of the country on the night of 7 September, leaving only a hurricane warning from Cabo Francés Viejo to Manzanillo Bay. Finally, the warnings were cancelled overall at around 10 p.m., although warnings of flash floods or slow-onset flooding and landslides remained in effect, and continuous monitoring of dams was maintained.

3.Most significant meteorological reports

  • Maximum accumulated rainfall in 24 hours: 99 mm in Monte Cristi(north-west), 78451
  • Maximum accumulated rainfall in 72 hours: 158.0 mm in Arroyo Barril (north-east), 78466
  • Minimum pressure reported: 995.1 mbsin Sabana de La Mar (northeast)
  • Maximum sustained winds: 56 km/hin Arroyo Barril (north-east)
  • Maximum wind gust: 111 km/hin Arroyo Barril (north-east).

/ NATIONAL METEOROLOGICAL OFFICE
Department of Hydrometeorology
Special map of Hurricane Irma
Accumulated rainfall values (72hours)
6-7-8 September 2017
ONAMET

4.Impacts of Irma

  • People directly affected: 15,829
  • People indirectly affected: 1,885.696
  • Fatalities: 0
  • Total homes affected: 108
  • Aqueductsaffected: 62
  • Electrical circuits affected: 830 (northern sector: 644).

5.Tracking of HurricaneMaríaand issuing of watches and warnings

At 7 p.m. on Sunday, 17 September, the National Meteorological Office Specialized Information Centre saw the need to issue an early weather warning from SaonaIsland to Cabo Engañoand from Cabo Engañoto Cabo Frances Viejo. At that time,Maríawas located some 200 kmeast/north-eastof Barbados, Windward Islands, Lesser Antilles, producing winds of 120 km/hand moving west/north-westwardat around 24 km/h.

The early weather warning remained in effect until 7 p.m. local time on Monday, 18September, when it was changed to a watch in coordination with the Regional Specialized Meteorological Centre: a hurricane watchwas issued from SaonaIsland to Cabo Engañoand from Cabo Engañoto Puerto Plata, as well as a tropical storm watch from Puerto Plata to Manzanillo Bay. Maríawas category 4 with maximum sustained winds of 215 km/h, located some 45 km south-east of Dominica, Lesser Antilles,and around 845 km south-east of Cabo Engaño, moving in a westerly/north-westerly direction ataround15 km/h.

At 1 p.m. local time on Tuesday, 19 September, ONAMET coordinated changes with the Miami Regional Specialized Meteorological Centre,issuing a hurricanewarning from Cabo Engaño to Puerto Plata and a tropical storm warning from Puerto Plata to Manzanillo Bay, on the border with Haiti. It also issued a tropical stormwarning from Cabo Engaño to Punta Palenque in the south. Maríawas category 5,with maximum sustained winds of 260 km/h, moving in a westerly/north-westerly direction at around 17 km/h, when it was located 225 km south-east of Saint Croix and around 555 km south-east of Cabo Engaño.

The warnings remained in effectin the afternoon of Wednesday, 20 September;while the centre ofMaríawas located around 140 km east of Cabo Engaño, the hurricane’s circulation was already affecting the Dominican Republic. Meanwhile, observations from the airports of Punta Cana, La Romana, Las Américas, Arroyo BarrilandSamana reportednorth-easterly and north/north-westerly winds with gusts exceeding 50km/h.In addition, moderate to intermittently heavy rain began to be observed in the eastern and north-eastern parts of the country. After making landfall in Puerto Rico, Hurricane Maríaweakened to Category 3, with winds of185km/h.

On the night of Wednesday, 20 September, whenMaríawas located approximately 75 km north-east of Cabo Engaño, moving north-westward at around 19 km/h, the maximum sustained winds had not significantly changed, and meteorological observation from the airports of Punta Cana, La Romana, Las Américas, Arroyo BarrilandSamanacontinued to report gusts of 80 km/h. It is also worth noting that Punta Cana reported 75 mm of accumulated rainfall in two hours. This continued to increase, reaching 111 mm at Punta Cana in 12 to 18 hours, while the same observatory reported wind gusts in excess of 100 km/h.

In the early hours of the morning on Thursday, 21 September, whenMaríawas located around 90 km north-east of Cabo Cabron, Samana, wind gusts of between 100 and 116 km/hwere reported at Samana International Airport, while gusts of 103 km/h, 83 km/h and 72 km/h were reported at Arroyo Barril, La Romanaand Punta Cana respectively. The warnings issued remained unchanged. Over the following hours, ONAMET lifted the tropical storm warning from Punta Palenque toAndrés, Boca Chica, maintaining it from Andrés, Boca Chicato Cabo Engaño. Meanwhile, the hurricane warning remained in effect from Cabo Engañoto Puerto Plata, as did the storm warning from Puerto Plata to Manzanillo Bay. At that point, a second, closer location reference was given for María, when it was around 85 km north/north-east ofSamana.There were also reports of between 75 and 130 mm of accumulated rainfall in localities in the north-east and central area of the Dominican Republic, as well as wind gusts exceeding 100 km/hin Samana, Sabana de La Mar, Arroyo Barriland Punta Cana.

At 4 p.m.on Thursday, 21 September, theonly warnings remaining in place were of hurricane conditions from Cabo Engañoto Puerto Plata,and of tropical storms from Puerto Plata toManzanillo Bay, while the storm warning for the coastal stretch from Andrés, Boca Chicato Cabo Engaño in the south-east of the country was lifted. Maríawas about 155 km north-east of Puerto Plata and some 105 km from Cabrera, moving north-westward at around 15 km/h, with maximum sustained winds of 195 km/h, which kept it as Category 3 hurricane on the Saffir-Simpsonscale.

Although the centre of Maríahad begun to move away by the early hours of Friday, 22 September, and the threat was diminishingin the Dominican Republic, the National Meteorological Office, in coordination with the Regional Specialized Meteorological Centre,decided that the warnings should remain unchanged, as it was feared that the civil protection bodies and the general public might underestimate the rainfall and cloud activity that was continuing over the country, accompanied by winds, some as strong as gusts, and abnormal surges.

At 10 a.m. on Friday, 22 September, the warning in effect was finally lifted, leaving the civil protection bodies to handle local warnings of flash floods or slow-onset flooding, as well as warnings to shipping traffic along the coastal perimeter.

6.Most significant meteorological reports

  • A private automatic weather station in Hato Mayor (east), reportedover 400 mm accumulated rainfallin 48 hours. There was severe flooding in the eastern region as well as river flooding.
  • The minimum pressure of992.8 mbs was observed at Samana International Airport (north-east), on Thursday, 21 September, at 09:00UTC.
  • The maximum sustained wind was the 40 kts (75 km/h) north wind reported at Arroyo Barril (north-east)at 15:00 UTC on Thursday, 21September.
  • The peak gust observed was northerly, at74 kts (137 km/h) in Arroyo Barril (north-east).
  • The maximum accumulated rainfall of 238.9 mm, was reported on 21September 2017 in Sabana de La Mar(north-east).
  • The maximum accumulated rainfall was recorded between20 and 22September, 327.2 mm atSabana de La Mar (north-east), followed by 311.0 mm at Arroyo Barril, Samana (north-east).

/ NATIONAL METEOROLOGICAL OFFICE
Department of Hydrometeorology
Accumulated rainfall from Tropical Hurricane María
ONAMET
20 to 21 September 2017

7.Impacts ofMaría

  • People directly affected: 1,752,415
  • People indirectly affected: 2,628,623
  • Injured: two
  • Fatalities: two
  • Communities cut off: 73
  • Bridges affected: 14
  • Roads:five
  • Homes destroyed: 1,573
  • Homes severely or slightly damaged: 1,968
  • Homes flooded: 10,636
  • Aqueducts: 128
  • Irrigation districts:nine
  • Schools: 83
  • Displaced tourists: 4,500

______