Preliminary Report
Hurricane Bertha
24 July - 02 August 1990

1990 PRELIMINARY REPORTS

Tropical Storm Arthur (TS)
Hurricane Bertha (1)
Tropical Storm Cesar (TS)
Hurricane Diana (2)
Tropical Storm Edouard (TS)
Tropical Storm Fran (TS)
Hurricane Gustav (3)
Tropical Storm Hortense (TS)
Hurricane Isidore (2)
Hurricane Josephine (1)
Hurricane Klaus (1)
Hurricane Lili (1)
Tropical Storm Marco (TS)
Hurricane Nana (1)

Bertha was an Atlantic hurricane that originated from a non-tropical area of low pressure near Cape Hatteras, North Carolina. The northern portion of a tropical wave, however, did interact with the system during its formative stage.

 

a. Synoptic History

A tropical wave emerged from the northwest coast of Africa on 15 July and split on the 20th in the mid-tropical Atlantic with the northern portion organizing briefly several hundred nautical miles east-northeast of the Leeward Islands on the 23rd. Meanwhile, a trailing tropical wave was in the process of developing into Tropical Storm Arthur and a frontal system was approaching the east coast of the Unites States. by 1200 UTC on the 24th, a low pressure area formed just southeast of Cape Hatteras, North Carolina, ahead of the frontal zone.

The northern portion of the tropical wave disorganized rapidly due to the shearing while continuing northwestward and the Hatteras low moved southeastward in association with an upper low. By 1800 UTC on the 25th while Arthur was entering the Caribbean Sea, the northern portion of the original tropical wave was approaching the Hatteras low, and that low began recurving southwestward toward Florida. The first satellite classification of the system occurred then.

For the next 36 hours, the low pressure system continued drifting southwestward with little change in strength. In retrospect, it is estimated that Tropical Depression Three formed 290 nautical miles east of Daytona Beach near 0600 UTC, 27 July. The tropical depression drifted to within 245 nautical miles east-northeast of Cape Canaveral, Florida before looping cyclonically northeastward. Based on 40-mph sustained winds reported by the Russian ship "Akademik Zavaritsaky" (UNUG), the depression was deemed to have reached tropical storm strength at 0000 UTC on the 28th. The first of 40 Air Force reconnaissance aircraft fixes for Bertha over the next four days was at 0316 UTC on the 28th. That fix revealed 61-mph winds at the flight altitude of 1500 feet.

Tropical Storm Bertha drifted northeastward during the 28th. Air Force reconnaissance reports from 2100 UTC on the 28th to 0000 UTC on the 29th showed 90-mph winds at 850 mb and extrapolated surface pressures in the vicinity of 990 mb. Thus, the system is estimated to have reached hurricane strength near 0000 UTC, 29 July, 465 nautical miles west-southwest of Bermuda. At that time, ridging from a strong Bermuda high extended across to the northeastern United States.

Hurricane Bertha experienced strong shearing while continuing northeastward and weakened to a tropical storm at 1800 UTC on the 29th with the center displaced from the convection. There was some speculation as to whether or not Bertha was becoming subtropical during this period because the deep convection was 60-180 nautical miles from the center. However, deep convection returned progressively closer to the center and the center was under the central dense overcast by 1200 UTC on the 30th. An Air Force reconnaissance plane at 1102 UTC found 92-mph winds at the 1500-feet flight level with a surface pressure of 988 mb. Thus, Bertha became a hurricane again near 1200 UTC, 30 July, 255 nautical miles east of Cape Hatteras, North Carolina, six days after Bertha's incipient stage as a low pressure area just southeast of Cape Hatteras.

Hurricane Bertha, with an increasing expanse of tropical storm force winds, continued moving northeastward as the ridge to the north was eroding. Bertha took a slight jog to the left when the Bermuda/Azores high coupled with a new high cell over Newfoundland. Subsequently, the Newfoundland high moved southeastward over the Grand Banks and Bertha jogged back to the right to its original course toward the Maritime Provinces. The system was taking on extratropical characteristics by then and began accelerating on 1 August with the center passing just west of Sable Island late on the 1st. Bertha was declared extratropical at 0600 UTC on the 2nd with the center directly over Sydney, Nova Scotia at that time. The weakening extratropical system continued northward over the eastern Gulf of St. Lawrence.

b. Meteorological Statistics

For most of its life, Bertha was primarily of concern to marine community with numerous ships reporting sustained winds in the 40 to 58-mph range. The lowest reported pressure of 985 mb was from the Canadian ship "A.S.L. Sanderling" (VOLG).

While the available surface observations do not reflect the strong winds associated with Bertha, the broad circulation did produce high surf along the Atlantic coast from Nova Scotia to North Carolina. Moderate beach erosion occurred along the coast of North Carolina and the Outer Banks. Moored bouy 44137 located at 41.1°N, 61.1°W reported 65-mph winds, with a significant wave height of 25 feet and a maximum wave height of 50 feet at 1700 UTC, 1 August.

At landfall, the center of Bertha was moving northward at 23 mph.

1. Rainfall Data

c. Casualty and Damage Statistics

There were 9 deaths attributed to Bertha; 2 in Florida and 7 in Nova Scotia.

According to The Chronicle-Herald, published in Halifax, Canada, twenty seven crew members of the 593-foot Greek Freighter "Corazon" abandoned ship 11 hours after reporting that the ship was breaking up. Thirty-feet waves whipped up winds gusting to 90 mph snapped its keel. One of the crew members fell into the water and drowned while trying to boad either a lifeboat or a rubber raft. He was pulled from the water dead by the crew of the Russian trawler Vympel. The crew of the Vympel attempted to rescue what was reported to be 12 sailors in a rubber raft but the raft was pulled into the trawler's propeller and rudder area and 6 or 7 sailors were pitched into the ocean. Five of them were taken aboad the Nova Europa, a freighter registered in Hong Kong. Another Russian Freighter and a Norweigian merchant ship also picked up crew members. A total of 6 crew members of the Corozon perished; 21 were saved.

A verbal communication from the Rescue Coordination Center at Scott AFB stated that a seaman was swept off the "Patricia Star", a 240-foot container ship, and lost while attempting to secure a deck load in heavy seas with winds estimated at 58-75 mph.

According to The Miami Herald, Bertha was blamed for rip currents that drowned 2 people at north Florida beaches; 200 others were rescued.

The Chronicle-Herald stated that several people were rescued at Peggy's Cove, Nova Scotia when 15-feet waves from Bertha washed them into the sea.

A total of 9 people perished as a result of Bertha.

Damage was reported to a suspension bridge near Warren Lake, Cape Breton, Nova Scotia, and parts of the Ingonish Beach Golf Course were flooded. Wind and heavy rain damaged corn and tobacco crops on Prince Edward Island.