Effects of 2020’s Hurricanes “PAULETTE”, “TEDDY” and “EPSILON” on Bermuda’s Nature Reserves
Jeremy Madeiros | Principle Scientist – Terrestrial Conservation, Dept. of Environment and Natural Resources
2020 has seen one of the most active Atlantic hurricane seasons in recorded history, with 29 named Tropical Storms and Hurricanes as of the writing of this report. Considering the large number of Hurricane strikes that Bermuda has experienced in recent years, it was perhaps inevitable that the island would receive its share. And sure enough, in September the island experienced the effects of not one, but two hurricanes only one week apart, followed by another near-miss in late October.
As of the writing of this report, all Nature Reserves on Bermuda have now been cleared of fallen trees and branches, and walking trails have been opened up and cleared of obstructions. On the offshore Nonsuch Island Reserve, some trenching work associated with a planned upgrade to the island’s solar power system and live-cam network and minor hurricane repairs to the buildings are ongoing, so the island remains closed to tours at present.
Eye of Hurricane Paulette approaches Bermuda September 14th 2020
Hurricane “Paulette” a borderline Category 1/Category 2 Cape Verde – type hurricane, formed in the central Atlantic Ocean and approached Bermuda from the east-southeast during the 2nd week of September, 2020. Unlike several recent hurricanes, such as Faye and Gonzalo in 2014, Nichole in 2016 and Humberto in 2019, which approached Bermuda from the southwest or west and produced significant wind damage but less storm surge and ground swell than would be expected, Paulette approached the island from the southeast as a strong Tropical Storm, strengthening into a Category 2 hurricane as it passed directly over Bermuda on the morning of 13th September. Winds were recorded as gusting from 89 mph to well over 100 mph in higher and exposed locations. The calm, 40-mile wide eye spent almost 3 hours over the island, after which the winds changed from east-northeast to west-southwesterly, with strong winds continuing for most of the remainder of the day.
Hurricanes approaching from the southeast always seem to produce the largest ground swells and storm surges, compared to storms approaching from any other direction. Following hurricane “Paulette”, a quick visit was made to Nonsuch Island and the other islands in the Castle Harbour Islands Nature Reserve, to assess any damage that may have occurred from the hurricane’s 80 – 100 mph winds and 20-foot waves and storm surge.
Following close behind the first hurricane, the much more powerful Hurricane “Teddy” also approached Bermuda from the southeast, attaining Category 4 strength with 150 mph (241 kph) sustained winds on the 17th September when some 930 miles southeast of Bermuda. This storm weakened as it neared Bermuda and veered at the last minute, passing 130 miles east of the island on the 21st September, sparing the island the worst of its winds but hammering the southern coastline for three days with waves reaching 21’ to 28’ in height.
Damage in most of the island’s Nature Reserves following the two September hurricanes was fairly limited, consisting mainly of downed trees and branches and considerable tidal flooding and erosion in coastal reserves such as Spittal Pond Nature Reserve and Coopers Island Nature Reserve. Spittal Pond was extensively flooded by hurricane waves flooding in through the low points at each end of the pond, raising water levels by over five feet for a couple of days and flooding portions of the walking trails and the woodland pond. A large boulder weighing over a ton that had hindered access to the “checkerboard” rock formation at the west end of the pond was flipped over, re-opening the easier access for the first time in a number of years. At Coopers Island, the access roads to the outer promontory were flooded and covered with sand, and the cliffs of the outer headland showed numerous scars where large chunks of limestone were torn out by the pounding surf.
The Castle Harbour Islands are Bermuda’s most important Nature Reserve, containing many of Bermuda’s most endangered and unique species and habitats. As it is much more exposed near the edge of the reef line, and faces towards the southeast, the direction that both of this year’s hurricanes approached from, this reserve suffered substantial impacts.
Preliminary assessments were carried out on the 16th and 23rd September, after each hurricane had passed. Most of the Castle Harbour Islands showed considerable erosion, loosing large chunks of their coastal cliffs and showing numerous white scars where sections of weathered gray limestone were wrenched off. Cliff damage and erosion was particularly noticeable on Castle Island, Southampton Island, the east and south coastlines of Nonsuch Island, Coopers Island Point and Inner Pear Rock. A large section of the rampart wall fortifications on Castle Island, dating from the mid-1600s, was undermined and collapsed from the heavy surf coming in through the Castle Roads channel, which also removed large sections of limestone along the south and southeast side of the island.
The buildings on Nonsuch Island had been fully secured and boarded up by both conservation officers before the hurricane and suffered no visible damage. The stairway up from the dock was completely blocked by large, uprooted Bay Grape trees, otherwise, there was little damage to the restored native vegetation on the island. The coastal areas on the island suffered the worst impacts, with the smaller beaches on the island being washed away and considerable erosion damage to the island’s coastal cliffs. A number of Nonsuch’s nearly 200 Tropicbird (Longtail) nests were damaged or destroyed, although a complete assessment was not possible immediately.
The two Cahow nesting colonies established over the last 10 years on Nonsuch Island were essentially untouched, as they were specifically placed high enough to be above the erosion zone of even the most severe hurricanes. However, the same could not be said for the four original smaller Castle Harbour islands on which the majority of the population of Bermuda’s Endangered National Bird still nests.
A full assessment was made after the seas calmed down from the passage of hurricane “Teddy” on the 21stSeptember, which produced three days of even larger, more damaging ground swell than was the case with Paulette. Damage on the smaller nesting islands, in particular, was severe, and possibly the worst since hurricane “Igor” in 2010. Two of these islands were completely submerged under the 20-28 foot waves of Paulette and Teddy, and checks made on both of these islands (Green Island and Long Rock) revealed that two-thirds of the concrete nest burrows used by Bermuda’s endangered National Bird, the Cahow, were made unusable by the waves sweeping across the island, rolling boulders weighing hundreds of pounds over the nest burrows and washing the heavy concrete lids, through which the birds can be observed and removed for banding and measurement, off the islands.
Two volunteer scuba divers from the Grotto Bay Beach Hotel, Robyn Vincent and Holly Wakeley, came out on the 29thSeptember to dive up the heavy concrete Cahow nest lids, that had been swept off into 25 to 30-foot deep water off Green Island, and 10 to 15-foot deep water off Long Rock. They were successful in retrieving almost all of the concrete lids, which can weigh up to 30lbs, greatly shortening the repair time to make the nest burrows ready in time for the return of the Cahows for the start of their nesting season in late October. Some nests needed repairs with fresh concrete to repair sections of the nest burrows that had been broken away, and almost all burrows needed large amounts of rocks and debris washed into the nests to be cleared out. Almost all work was finished in time by mid-October, until word was received of yet another Hurricane headed for Bermuda.
Despite hopes that Bermuda would suffer no more hurricane impacts, the high tropical activity of 2020 continued, and on the 21st October, hurricane “Epsilon” formed to the southeast of the island, rapidly strengthening to Category 3 strength and passing about 165 miles to the east of Bermuda during the 23rd October. Although this storm passed far enough away that the island experienced only Tropical Storm-force winds, the south and eastern coastlines were again pounded by 18’ to 20’ storm waves for two days as Epsilon moved by, affecting the same areas that suffered erosion during the September hurricanes.
Once again, Long Rock and Green Island were inundated by large storm swell and surge. Many of the concrete nest lids just recently recovered were swept off again, and nest burrows filled with rocks, with the sandy substrate that the Cahows nest on in the nest burrows being washed out. Further significant erosion was also caused to the coastal cliffs and shoreline along South Shore. New large white scars where large areas of limestone were ripped away appeared in addition to those already caused by the two September hurricanes. Spittal Pond N.R. once again suffered flooding, although not to the extent it did during “Paulette” and “Teddy”. Many of the Islands in the Castle Islands Nature Reserve suffered significant additional erosion, in particular Charles Island, Castle Island, Southampton Island, Nonsuch Island, Coopers Island Point, Inner and Outer Pear Rock, and Long Rock. Inner Pear Rock (Outer), which is one of the original four nesting islets and the location of the Cahow’s rediscovery in 1951, suffered particularly heavy erosion and almost all of the huge collapsed boulders that enabled access from the western half of the island to the eastern half, which contains a number of Cahow burrows, have been swept away. An extension ladder will now be required to safely access this area. Luckily, despite the erosion, only one inactive Cahow burrow was damaged, but continuing erosion to most of the original nesting islets is making them increasingly hazardous as nesting sites for this species. This is in contrast to the newly established, growing Nonsuch nesting colonies, which were unaffected by all three hurricanes.
Bermuda’s nesting population of the Longtail, or White-tailed Tropicbird, is the largest in the North Atlantic basin at about 3500 pairs and is of international importance for the species. Many of the largest concentrations of Longtails nest in cavities along the cliffs of the South and East Coastlines of Bermuda, where erosion from the three hurricanes of 2020 was concentrated. The Castle Islands Nature Reserve have the largest concentration of nesting Longtails in Bermuda (in fact the largest single concentration of White-tailed Tropicbirds in the entire North Atlantic!) at 550-600 nesting pairs. Over 250 of these Castle Harbour nests have been monitored by me since 2006 for a study of breeding success rates and population dynamics, and I have been able to confirm that at least 36 of these study nests have been destroyed or rendered unusable. This represents almost 15 % of the active nests in this area, and based on this, the total number of destroyed nests along the entire South Shore may easily number in the hundreds. One important fact is that the artificial “Igloo” Longtail nests produced in partnership with the Bermuda Audubon Society after a large loss of natural nests during hurricane “Fabian” in 2003, suffered almost no losses. These nests can be installed in higher elevated locations less vulnerable to erosion, and are cemented securely to the cliff edges. Over 100 of these artificial nests have been installed in this area, and only 3 were destroyed or damaged in this year’s hurricanes. There are a small number of igloo nests reserved in storage on Nonsuch, and it is planned to install all of these over this winter, on the islands where Longtail nests were destroyed, to offset the nest loss and enable this population to maintain its present healthy numbers.
Jeremy Madeiros, Principle Scientist – Terrestrial Conservation, Dept. of Environment and Natural resources