USA – Storm Surge and Heavy Rain From Hurricane Isaias Triggers Flooding

Tropical Cyclone Isaias strengthened into a Category 1 hurricane on Monday, 03 August, prior to making landfall near Ocean Isle Beach in North Carolina, USA. Since then, at least 6 people have died in the USA as the storm made its way north, spawning tornadoes and bringing heavy rain and sustained winds of over 100 km/h.

Storm surge caused coastal flooding in parts of North and South Carolina. Emergency services were called on to rescue people trapped in flooded homes in Brunswick County, North Carolina. More than 3,000 people were evacuated from Ocracoke Island, part of North Carolina’s coastal Outer Banks region.

Observed water levels at Wilmington, NC, reached 4.19 feet / 1.27 metres (Mean higher high water – MHHW), well above Moderate Flood Stage of 2.75 feet / 0.83 metres, as of 04 August, according to NOAA. (Note: updated to show correct measurements in feet and metres.)

Wilmington NC, USA, tide floods during Hurricane Isaias – NOAA Tides Currents

Further north, heavy rain triggered flooding in Pennsylvania, where one person died after a vehicle was swept away by flood waters in Upper Saucon Township near Allentown, eastern Pennsylvania.

NWS estimate as much as 7 inches / 177 mm of rain fell in 6 hours on 04 August, adding that “rivers are quickly rising due to this excessive rainfall.”

Jordan Creek at Allentown reached 11.82 feet as of early 05 August, beating the previous record high of 11.61 feet set in 1972.

Flooding was also reported in Montgomery County, where the Schuylkill River at Norristown reached Major Flood Stage on 04 August.

At least 5 other deaths in the USA were blamed on the storm as a result of wind damage or tornadoes.

Isaias became a Post-Tropical Cyclone as it moved into Canada, where it is “producing gusty winds and heavy rainfall over southeastern Quebec,” according to the National Hurricane Center (NHC).

Levels of the Schuylkill River at Norristown during Storm Isaias early August 2020 – NWS


Levels of Jordan Creek at Allentown during Storm Isaias, August 2020 – NWS


Estimated rainfall in Eastern USA brought by Hurricane Isaias, 04 August 2020. Image: NWS


Previously Isaias had swept over parts of the Caribbean, with 2 fatalities reported.

The United Nations said the storm caused “damage and outages in The Bahamas, the Turks and Caicos Islands (TCI), the Dominican Republic and northern Haiti.” The affects of the storm were also felt in Puerto Rico and Cuba.

In Puerto Rico, National Guard troops rescued 35 people in Mayagüez. One person died after a vehicle was swept away by flood waters in Rincón.

The Dominican Republic’s Emergency Operations Centre (COE) reports that Isaias affected 1,000 homes and prompted the evacuation of 5,000 people. Some 130 communities were cut off after flooding blocked roads. One person died when a high-voltage line fell due to strong winds.

In Haiti, disaster authorities reported limited impact along the northern coasts with around 40 damaged buildings. Around 100 buildings were reported damaged in eastern Cuba. Parts of TCI experienced strong winds, some flooding and power outages.

Around 30 people were evacuated in the Bahamas. As of 04 August, authorities in The Bahamas reported minimal damages in islands, with further assessments to be carried out.

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