Nineteen tropical and subtropical storms developed in 2011 over the Atlantic Basin (North Atlantic Ocean, Caribbean Sea and the Gulf of Mexico), but only seven of these became a hurricane and three reached major hurricane intensity (category 3 to 5).
Before the start of the season, 16 named storms were forecast to develop during the season, nine would become a hurricane and five a major hurricane. The amount of tropical storms was well above average. However, the amount of hurricanes and major hurricanes stayed a little behind the predicted numbers. Seven tropical cyclones developed over the Atlantic Basin in 2011 before Irene, the eighth system of the year, became a hurricane. Irene also became the first major hurricane and besides the SSS Islands and Puerto Rico, also had a major impact on parts of the eastern and northeastern United States of America. The strongest hurricane of the season was Ophelia. This system became a category four system over the northwestern North Atlantic, well south of southeastern Canada and never affected any island or country..
The activity during the 2011 season, as far as the amount of named storms is concerned, can be compared to the 1887, 1995 and 2010 seasons.
Three of last season’s systems, tropical storms Emily, Irene and Maria posed a threat to the SSS Islands during parts of August and September. Only Irene actually caused tropical storm conditions on these islands.
The ABC Islands on the other hand were not threatened at any time by a tropical cyclone during the 2011 hurricane season.
Tropical Storm Emily developed during the evening of August 1 well south of the SSS Islands, near Dominica. Since the tropical storm force winds were forecast to stay well away from the SSS Islands, the Meteorological Department Curaçao (MDC) did not issue any watches or warnings for these islands. Information bulletins and also a Small Craft Advisory on this system however were issued between the morning of July 31, when it was still an area of low pressure and August 2, when it was tropical storm Emily and was moving away from the region, in a westerly direction. Emily caused fresh to strong easterly winds in the SSS Islands and mainly St. Maarten got a few moderate to heavy showers on parts of August 1 and 2.
Tropical Storm Irene formed during the late afternoon of August 20, when its center was located just east of the eastern Caribbean island chain. Since the center of this system was expected to pass rather close to the SSS Islands during the next morning, a Tropical Storm Warning and a Small Craft Warning were immediately issued.
During the night, the center of Irene redeveloped farther north and therefore the center would move closer to the SSS Islands on Sunday morning.
During the late morning, the center passed at a distance of approximately 35 miles south of St. Eustatius. A wind gust up to 61 mph was measured at this island’s
Roosevelt Airport, while the pressure dropped to 1003 millibars. The observed amounts of rain in these islands in general were not impressive and between 25 and 50 mm (1- 2 inches). During that afternoon, Irene moved away from the region and the tropical storm warning was discontinued later in the day.
Irene moved over Puerto Rico on the next day, where it became a hurricane during the early morning. After it moved away from that island, it went on to strengthen further o a major (category 3) hurricane, while located over the northwestern Bahamas. On Friday, August 26, it started a gradual weakening trend and reached the east coast of the United States in North Carolina on the next day as a category two hurricane.
Despite this weakening, it still caused a significant amount of damage and a few victims in parts of several states in the eastern and northeastern U.S.A.
Tropical Depression Fourteen formed over the eastern tropical Atlantic Ocean on September 6. It became Tropical Storm Maria the next morning and preliminary
forecast guidance indicated that this system would pass rather close to the SSS Islands three days later. That was the reason to start issuing Information Messages for the authorities and population of these islands as soon as the afternoon of that same Wednesday. A Tropical Storm Watch was issued on Thursday (September 8) but this system started to weaken, as it got closer to the eastern Caribbean Area. A Tropical Storm Warning was still issued late that same (Thursday) evening but Maria was at minimum tropical storm intensity, when it moved just northeast of the SSS Islands during the morning of Saturday, September 10. Since the strongest winds associated with this system would stay well northeast of these islands, the tropical storm warning was discontinued and replaced by a Tropical Storm Advisory that same morning. A tropical storm or hurricane advisory is issued by the MDC, when no tropical storm or hurricane force winds are expected, but that heavy rain and/or rough seas may still cause a significant impact in a certain region.
Maria caused a few showers in the SSS Islands on September 11 but the amounts observed were in general less than 25 mm (1 inch). The winds became northeasterly on the 10th and shifted later in the day to the south or southwest. A few gusts were recorded at the airports of St. Maarten and St. Eustatius, but these were all below tropical storm intensity.
Although the hurricane season has ended, it is important to stay alert for other natural hazards, such as heavy rainfall causing flash flooding and also for large swells
generating rough seas on our shores.