Storm surges and hurricanes in New Jersey: Everything you need to know

Although New Jersey's coastal communities have a history of dealing with extreme weather, rising sea levels are introducing new risks.

While average global sea level has risen about 8 inches since 1900, New Jersey's sea level crept higher – about 17 inches over the same period, according to a report by Rutgers University. New Jersey's remarkable sea level rise is due to the land sinking because of groundwater pumping and natural geological processes related to the last glacial period.

Higher sea levels mean that less powerful storms create seawater overflow onto coastal lands, flooding streets and damaging property. Specifically, when a hurricane hits New Jersey, the greatest threat to both life and properties is a storm surge, according to a report by Rhodium Group, a research institute in New York City.

During Superstorm Sandy, 38,000 New Jersey residents experienced flooding who would have not been affected if sea levels remained at the levels in the 1880s, the Rhodium Group report states.

New Jersey's extensive 1,792-mile coastline holds a crucial role in both the state's economy and the lifestyles of some of its residents. Seventeen out of the state's 21 counties border some part of this coastline. These counties are home to roughly 80% of New Jersey's 9 million residents and account for more than $400 billion in annual economic output, according to the Rhodium Group report, co-authored by scholars from Rutgers University, UC Berkley and the University of Chicago.

High winds and storm surge have hit the Jersey Shore's beaches in years past, but the risks are increasing these days.
High winds and storm surge have hit the Jersey Shore's beaches in years past, but the risks are increasing these days.

What is a storm surge?

A storm surge is when storm-driven winds push water toward the coastline. As the tide rises, the water overflows onto coastal lands, causing flooding.

Since the 1980s, the frequency and extent of storm surges has grown so much that between 62,000 and 86,000 properties, worth a combined value of more than $60 billion, will flood at least once during a 30-year mortgage period, reports the Rhodium Group.

When is hurricane season?

Hurricane season runs from June 1 through Nov. 30.  Most hurricanes occur between August through October, with September being the busiest month.

Is New Jersey getting more tropical storms now than before?

Since the 1960s, New Jersey had been hit by six to seven tropical storms every 20 years, according to the National Oceanic and Atmospheric Administration's Historical Hurricane Tracks. The last four tropical storms to reach New Jersey were: Elsa in July 2021, Isaias in August 2020, Fay in July 2020 and Sandy in October 2012. None of these tropical storms were considered hurricanes by the time they arrived here. Sandy was a category 1 hurricane and weakened to a tropical storm just a few hours before making landfall.

Since the 1850s, 55 tropical storms have passed by the Garden State. That number is 333 for Florida and 174 for Louisiana, according to NOAA.

More: Jersey Shore expected to have more high tide flooding days this fall and winter

What is the difference between a tropical storm and a hurricane?

All hurricanes are tropical storms. When a tropical storm grows into a cyclone with surface winds of 74 mph or greater, it gets classified as a hurricane. Wind speed will determine the category of the hurricane as follows:

Hurricane category scale

Category 1: Very dangerous winds between 74 and 95 mph. Can cause damage to the roof of a framed home. Tree branches can snap.

Category 2: Extremely dangerous winds between 96 and 110 mph. Framed homes can sustain major roof and siding damage. Trees with shallow roots can be uprooted.

Category 3: Devastating winds between 111 and 129 mph. A framed home can lose its entire roof. Many trees will be snapped or uprooted. Electricity and water may be unavailable for several days.

Category 4: Catastrophic winds between 130 and 156 mph. Framed homes can fall apart, losing walls and roofs. Most trees will be snapped or uprooted, and power poles downed. Power outages can last months.

Category 5: Catastrophic winds of 157 mph or higher. Most of the area will be uninhabitable for weeks or months. A high percentage of framed homes will be destroyed.

This scale doesn’t take into account other hazards such as storm surges, rainfall flooding and tornadoes. There have been hurricanes of lower categories causing more damage than systems of higher categories. Wind pressure, rainfall, and the angle at which the winds blow can determine how much damage a storm can cause.

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How many hurricanes have made landfall in New Jersey?

While 15 hurricanes have passed close to New Jersey since 1850, only one made landfall in the Garden State, according to NOAA's Historical Hurricane Tracks.

Dubbed as the 1903 New Jersey Hurricane, this tropical system made landfall in Atlantic City in September 1903. In Asbury Park, the storm wrecked the roofs of six hotels. High waves damaged the boardwalks at Belmar and Allenhurst. Fruit crops in Monmouth, Middlesex, and Hunterdon counties were severely damaged. In Flemington, about 75% of apples and pears were lost. Damage across the state was estimated at $8 million (equivalent to $279 million in 2023).

This article originally appeared on Asbury Park Press: New Jersey weather: What is a storm surge? When is hurricane season?