According to catastrophe modeling firm AIR Worldwide, the 17th named storm of the Atlantic hurricane season, Tropical Storm Rafael, is moving away from the Leeward Islands after battering the islands with strong winds and heavy rain. As of the National Hurricane Center’s (NHC) 11:00 AM EDT advisory, the storm is located approximately 170 miles northeast of San Juan, Puerto Rico and approximately 850 miles south of Bermuda. Rafael has maximum sustained winds of 60 miles per hour with tropical force winds that extend outward from the center an impressive 175 miles. The storm’s forward speed has slowed to 12 mph, which has allowed it to become more organized. A tropical storm watch is in effect for Bermuda.
“Rafael has entered an area favorable for intensification; sea surface temperatures are warm and wind shear is relatively weak,” said Scott Stransky, senior scientist at AIR Worldwide. According to the NHC, it is possible for the storm to gain hurricane intensity later today. The most likely track brings Rafael towards Bermuda on Tuesday.
Bringing strong winds and heavy rains, with accumulations of 2 to 4 inches, the storm downed trees and power lines, damaged roofs, and flooded low-lying areas throughout several Caribbean islands, including the Virgin Islands, Trinidad and Tobago, St. Kitts, and Antigua.
According to AIR, in these affected territories, building stock and code enforcement can vary widely. The common construction types for residential structures in the region include wood frame, unreinforced masonry, and reinforced masonry, although the distribution of these construction materials depend on local practices. In Saint Martin, for example, construction must comply with French building standards, resulting in a consistent and robust building inventory. On the Dutch side of the island, Sint Maarten, attention to design standards is not as uniform, and building stock tends to be constructed of weaker wood frame or unreinforced masonry construction.
Stransky continued, “Although the wind speeds are likely too low to cause significant damage, some locations may experience flood-related damage. Flood waters which penetrate into vulnerable wood frame and unreinforced structures can cause damage, primarily to the building’s contents. Auto damage may also be significant, particularly in places where floodwaters rise rapidly, leaving little time for their evacuation.”
“The most likely forecast track takes Rafael just east of Bermuda by Tuesday but it does not currently represent a risk to the U.S. Given that the radius of tropical storm force winds is about 175 miles (mainly to the east of the system), Puerto Rico and Bermuda will be right on the borderline of tropical storm-force winds, and will escape Rafael’s strongest winds. However, a shift in the track towards the west could bring stronger winds closer to Bermuda. Wind damage is expected to be minimal; its most substantial effect throughout the region will likely be from flooding.
The storm is expected to bring rainfall accumulations of three to five inches over the Lesser Antilles and the Virgin Islands with one to three inches expected in Puerto Rico. The heaviest rainfall—as much as 10 inches in isolated areas—
can affect the region’s mountainous areas, creating a risk of life-threatening flash floods and mudslides.
