Puerto
Rico and U.S. Virgin
Islands Severe Rainfall�
November
12-14, 2003
Heavy rains over Puerto Rico and the U.S.
Virgin Islands during the week of November
10-15 2003, led to widespread flash flooding, and numerous mud, land
and rock slides. In Puerto Rico, 19
municipalities were declared a federal disaster area, with total damages
estimated around 45 million. The U.S. Virgin Islands were also declared a
federal disaster area, with damages estimates around 25-30 million.
On November
10, 2003, an active tropical wave
approached the U.S. Virgin Islands and Puerto Rico as a mid to upper level low pressure trough advanced
towards Eastern Hispaniola from the Bahamas. All ingredients for heavy rains
were beginning to come together across the U.S. Virgin Islands and Puerto Rio.
As the strong tropical wave crossed the area from east to west, it set up a south to southeast wind flow over the Northeast
Caribbean that allowed for abundant low level moisture to slide into
the U.S. Virgin Islands and Puerto Rico. By Tuesday November 11, 2003, the strong
tropical wave evolved into a broad area of low pressure which developed across
the Caribbean
Sea southwest of Puerto Rico. This low
pressure at the surface extended from Hispaniola eastward into
the Leeward
Islands and was expected to slowly strengthen through Wednesday,
and to eventually move northeast.� A
reconnaissance aircraft flew into the suspect low pressure area on Tuesday, but
was unable to find a closed circulation center at the surface. However, it did
find that the lowest sea level pressure was just east of the Eastern tip of Hispaniola. The
combination of all these factors, an almost stationary broad low pressure, a� mid to upper level
trough to the west, southeast low level winds, and a plume of moist mid to high
level air stream from northern South America, led to a� period of widespread and continuous heavy
rains across all of the U.S. Virgin Islands and Puerto Rico, resulting in
generalized flash floods and river floods. The heaviest rains affected Puerto Rico through
Friday November 14, and the U.S. Virgin Islands through early Saturday morning,
November 15.
The period of
widespread and heavy rainfall tapered off after November 15, but it was
followed by a three day stretch of occasional showers associated to a cold
front, from November 15-18, for both the U.S. Virgin Islands and Puerto Rico.� The cold front approached from the northwest,
moving southeast across the local area Saturday, and reaching into the Leeward
Islands.� By late Sunday into
Monday, November 16, the low level trade�
winds became southeast across the Northeast Caribbean,� forcing the remnants of the cold front, to
move back over the U.S. Virgin Islands and Puerto Rico. Although rainfall
amounts were not significant across the U.S. Virgin Islands, the ground was so
saturated, that even small amounts of rain resulted in additional flooding, and
landslides. In Puerto Rico, many parts of the island
received heavy rainfall amounts, and the highest was again, in the municipality of Naguabo, where over
10 inches were recorded at the Rio Icacos USGS
sensor.�
The greatest rainfall amounts across Puerto Rico for the
period from November 12-14, varied from 10 to 20 inches, although the eastern Puerto Rico municipality of Naguabo received 21.01
inches.
The highest 4-day rainfall accumulation,
ending @ 0800AM� November 14th,
were recorded at : Naguabo - 22.70 in, Sabana Grande - 19.73 in, Ponce - 17.77 in, Rio Grande -
17.13 in,����� Guayama
- 17.09 in, and Aibonito - 15.79 in �( Tables 1- 4 ).�
The highest
rainfall intensity occurred in the upper part of Naguabo.
Comparison with TP- 42 charts indicated:�
the 50 yr - 4 day rainfall was exceeded in Naguabo
and Aibonito, and the 25 yr - 4 day rainfall was
exceeded in the south and eastern coastal plains from Juana Diaz to Naguabo as well as in the northern parts of Yauco, Aibonito and Guayama.
The highest 1
hour, 2 hour, and 3 hour rainfall totals of 2.95 inches, 3.97 inches, and 4.73
inches were recorded at Salinas, Sabana Grande and Naguabo,� respectively. The
highest 6 hour and 12 hour rainfall totals of 5.83 inches and 8.19 inches were
recorded at Sabana Grande.
Extreme river
rises were observed during the event. These were widespread around the island. Gaged sites that exceeded 15 feet rise were:
����������� Rio Grande de Loiza
below Damsite ������������������� �- 26 feet
����������� Rio Grande de Manati
at Hwy 2 near Manati�������� -
22 feet
����������� Rio Gurabo
at Gurabo��������������������������������������������� -
21 feet
����������� Rio Jacaguas
at Juana Diaz����������������������������������
- 20 feet
����������� Rio de La Plata at Hwy 2 at Toa Alta��������������������� - 19 feet
����������� Rio de La Plata below La Plata Damsite� - 18
feet
� ��������� Rio
de La Plata at Comerio ����������������������������������� - 16 feet
����������� Rio
Caonillas at Paso Palma��������������������������������� - 15 feet
����������� Rio Guanajibo
at Hwy 119 at San German����������� - 15
feet
����������� Rio Culebrinas
at Hwy 404 near Moca������������������ -
15 feet
�����������
The highest
reservoir water levels rises were observed at:
����������� Lago Cerrillos at Damsite near
Ponce��������� �������� �- 39 feet
����������� Lago Toa Vaca at Damsite������������������������� ���������� �- 16 feet
Rainfall
amount across the U.S. Virgin Islands for the period from November 10-15, varied from 10 to 15 inches. The recorded
rainfall intensity for St. Croix during the
period from November 10-14, exceeded the one hundred year return period. For St. John approached
the one hundred year return period, and for St. Thomas it was below
the 25 year return period.� Cumulative rainfall for the three day period beginning Saturday
November 16 at 8 am,
and ending Tuesday November 18 at 8
am, reflected rainfall amounts ranging
from 8-10 inches in the area of Naguabo to 4 to 6
inches in many other places of east and central Puerto
Rico. (See table�
�)
In the U.S.
Virgin Islands, rainfall varied from 2.6 inches in St. Thomas to 3.65 inches in
St. John.� This additional rainfall
exacerbated the pre existent flood situation even more, since not much rainfall
was needed to cause flooding.��
In Puerto Rico, flood effects on the
population were considerable. A total of 19 municipalities were declared a
federal disaster, Arroyo, Cabo Rojo,
Canovanas, Fajardo, Guanica, Guayama, Juana Diaz, Loiza, Luquillo, Maunabo, Naguabo, Patillas, Rio Grande, Salinas, Santa Isabel, Toa Baja, Yabucoa, and Yauco. The most
seriously affected were Guanica, Santa Isabel,
Salinas, Juana Diaz, Yabucoa and Maunabo.� Infrastructure and personal losses were
estimated at 8 million.� Agricultural
losses accounted for approximately $ 31 million. The greatest crop loss was
coffee, followed by plantains, oranges, and sugar cane.� Total damages amounted to around 45 million.
There were two deaths in Puerto Rico, one in Aibonito
by drowning and another in Ciales.� The highest rainfall fell in Naguabo. Approximately 860 people across the island were
forced from their homes into shelters due to flooding. Many bridges and roads
sustained damages.
There were many livestock lost due to
the flooding.
The rains were heavy in St Croix on
November 11 where around 8 inches accumulated. There were landslides from the
hills above Charlotte Amalie. Roads and culverts
flooded. Water and mud covered the streets. The commercial district in Christiansted was flooded with debris and mud. Some roads
in St Thomas were closed due to damage. The U.S. Virgin Islands government
estimated the losses at 25.5 million, St Croix 8.8M, St Thomas 10.6M and St
John 6.1M.
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