The final report on Hurricane Maria is in. It was written by Richard J. Pasch, Andrew B. Penny, and Robbie Berg from the National Hurricane Center. The report is almost 50 pages long but here are some of the highlights.
Maria was a long tracking "Cape Verde" hurricane that blasted several islands in the Caribbean. It hit Dominica as a category 5 hurricane and then devasted Puerto Rico as a high end category 4 hurricane. Even though Puerto Rico was the only United States impact, Maria was the 3rd costliest hurricane in U.S. history.
Maria began as an intense tropical wave over the African continent. It came off the West Coast of Africa as a strong wave on September 12, 2017. For 3 days it moved over the far Eastern Atlantic very quickly. That fast forward motion prevented the wave from closing up into a defined low pressure circulation. But, early in the day on September 16, it is estimated that Maria became a depression almost 600 miles east of Barbados. With ideal atmospheric conditions, Maria strengthened into a hurricane in just 30 hours. Just 18 hours later, Maria because a major hurricane. Maria continued its incredibly rapid intensification into a category 5 just 12 hours after that near Dominica. The hurricane made landfall on the island with 165 mph wind and an estimated minimum central pressure of 922 mb on September 19, 2017.
After striking Dominica, Maria continued moving west-northwestward and entered the northeastern Caribbean Sea. Slight weakening had occurred due to the system’s interaction with the mountainous island of Dominica, but the hurricane soon regained intensity and strengthened to its peak intensity of 172 mph with a minimum pressure of 908 mb on September 20, 2017. At that point it was just about 25 miles south of St. Croix. Maria moved west-northwestward to northwestward toward Puerto Rico and, after reaching maximum intensity, it went through eye wall replacement cycles. Although slightly weaker, it was larger when it hit Puerto Rico. Maria’s center crossed the southeast coast of Puerto Rico near Yabucoa in the morning on September 20, and the hurricane’s maximum winds at that time were near 155 mph, which is just below the threshold of category 5 intensity. With Maria entering in the southeast corner of Puerto Rico and moving WNW, it basically moved across the entire island. At this point it had slowed its forward speed somewhat and spent several hours ravaging Puerto Rico. With its long duration interaction with Puerto Rico, Maria weakened significantly and had 110 mph wind as it left the island.
Following its hit on Puerto Rico, Maria went toward the Turks and Caicos and the far Southeastern Bahamas before eventually weakening and turning north and then northeast out to sea.
WINDS AND PRESSURE
Maria’s peak intensity was 172 mph when it was 25 miles south of St. Croix on September 20.
Maria’s 65-kt (75 mph) intensity increase over 24 hours on September 18 makes it tied for the sixth-fastest intensifying hurricane in the Atlantic basin record.
Winds were 145 knots (165 mph) when it struck Dominica. Maria is the strongest hurricane on record to make landfall on Dominica in known modern records.
Maria’s minimum central pressure of 908 mb is the lowest pressure on record of any hurricane in the Atlantic basin east of 70°W, and breaks the record that had been set just a couple of weeks earlier by Irma of 914 mb.
The landfall intensity of Maria in Puerto Rico, was 135 knots (155 mph) It is likely that higher elevations did see category 5 wind speeds. This made Maria a strong CATEGORY 4 at landfall in Puerto Rico.
Maria is the strongest hurricane to make landfall in Puerto Rico since a category 5 hurricane in 1928 (known as Segundo San Felipe).
A peak sustained wind of 93 knots (107 mph) with a gust to 119 knots (137 mph) was reported at St. Croix near the northeast edge of Maria’s eyewall.
Las Mareas, on the south coast of Puerto Rico, recorded a sustained wind of 94 knots (108 mph) with a gust to 109 knots (125 mph) in the western eyewall of Maria.
Wind gusts to hurricane force were recorded in Guadeloupe and on the northeast coast of the Dominican Republic.
6 to 9 feet surge observations along the north coast of Puerto Rico
3 to 5 feet in St Croix
1 to 3 feet in St Thomas and St John
1 to 3 feet in North Carolina
No recorded information from Dominica as surge measurements aren't recorded there, but there appears to have been significant damage from a storm surge.
RAINFALL AND FLOODING
22 inches fell in Dominica. Up to 38 inches was observed in Puerto Rico. Due to the mountainous terrain, devastating mud slides and river flooding resulted in Puerto Rico as well. The most significant river flooding occurred in the La Plata River.
Maria caused 31 direct deaths in Dominica with 34 missing.
In Guadeloupe, two direct fatalities are attributed to Maria: one person died from a falling tree, and another was swept out to sea.
In Puerto Rico, the death toll is highly uncertain and the official number stands at 65, which includes an unknown number of indirect deaths. It should be noted that hundreds of additional indirect deaths in Puerto Rico may eventually be attributed to Maria’s aftermath pending the results of an official government review.
One person died from drowning, and another was killed by a mud slide in St. Thomas.
Four people were swept away by floodwaters, and another individual perished in a mud slide in the Dominican Republic.
Three people died due to floodwaters in Haiti.
In the mainland United States, three people drowned due to rip currents at the Jersey Shore, and there was a fourth drowning death at Fernandina Beach, Florida.
Maria caused catastrophic damage in Dominica, with the majority of structures seriously damaged or destroyed, and most trees and vegetation were downed and/or defoliated. According to media reports, the estimated damage total in Dominica is at least $1.31 billion. The agricultural sector was essentially eliminated. The once-lush tropical island was effectively reduced to an immense field of debris. In a Facebook post just after the hurricane hit, Dominica’s Prime Minister, Roosevelt Skerrit, described the damage as “mind-boggling”. The roofs of the majority of buildings and homes were either damaged or blown off. There was extensive damage to roads. Power, phone, and internet service was cut off, leaving the country almost incommunicado with the outside world. Figure 9 shows some examples of the damage in Dominica.
In Guadeloupe, to the north of Dominica, hurricane-force wind gusts and heavy rain caused a great deal of damage, especially along the southern portions of Basse-Terre Island. An estimated 80,000 homes were without electricity, and almost the entire banana crop was destroyed. An estimated $120 million in damage was reported for Guadeloupe.
Among all the U.S. Virgin Islands, St. Croix was the most severely affected by Maria, having experienced the northern portion of the outer eyewall. Wind damage was evident across the entire island with many fallen trees, downed signs, roof damage and complete destruction of many wooden houses. Excessive rainfall generated significant flooding and mud slides across the island. In St. Thomas and St. John, most of the roofs, signs and trees had already been destroyed or damaged earlier by Hurricane Irma, but large rainfall accumulations generated flooding and mud slides across all these islands.
Puerto Rico was devastated by winds and floods. The estimate of damage in Puerto Rico and the U.S. Virgin Islands due to Maria is 90 billion dollars, which makes Maria the third costliest hurricane in U.S. history, behind Katrina (2005) and Harvey (2017). Maria is by far the most destructive hurricane to hit Puerto Rico in modern times, as the previous costliest hurricane on record for the island was Georges in 1998, which in 2017 dollars “only” caused about 5 billion dollars of damage.
The mean official track forecast errors ranged from around 20 miles at 24 hours to around 120 miles at 120 hours. These errors were about 50 percent smaller than the mean official errors for the previous 5-year period at all forecast intervals. All of the official forecasts issued from the time of Maria’s formation up to the night before its second landfall correctly showed that the hurricane would strike Puerto Rico.
The mean official forecast intensity errors were 10 to 15 knots from 24 through 72 hours, but were less than 10 knots at days 4 and 5. These errors were 15 percent to 25 percent higher than the mean official errors for the previous 5-yr period through 48 hours, but 10 percent lower than the long-term mean at 72 hours and 35 percent to 45 percent lower at 96 and 120 hours.