High-wind events are a common occurrence in New York City (NYC). A variety of windstorm types can occur with little warning, damaging property and infrastructure, disrupting transportation, downing trees and power lines, and causing serious personal injuries.
New York City’s dense high-rise environment, high number of older buildings, and many open construction sites heighten its vulnerability to dangerous winds.
What is the Hazard?
Most New Yorkers recognize that they have to battle high winds from time to time, but not all high-wind events are caused by the same type of weather systems.
Hazardous high-wind events can occur from tight pressure gradients, strong frontal systems, nor’easters, hurricanes, and severe thunderstorms, which may produce straight-line winds or tornadoes.1NOAA National Severe Storms Laboratory, “Research at NSSL: Damaging Winds,” National Oceanic and Atmospheric Administration. High-wind events may or may not be accompanied by precipitation and can vary in geographic extent, intensity, and duration. For example, events can range from short bursts of high-speed winds, such as with a severe thunderstorm, to longer periods of sustained winds from events such as a hurricane. Severe thunderstorms typically have less than an hour of warning lead time, but nor’easters, tropical cyclones, and other types of high-wind events usually have several hours to a few days of warning lead time.
| High-Wind Events | Characteristics |
|---|---|
| Straight-line Winds | – Most common with storms – Typically blow in one direction, but can vary during the course of the event – Speeds exceeding 50–60 miles per hour (mph) – Associated with intense low atmospheric pressure – Duration of up to one day |
| Thunderstorm | – Storms capable of producing high wind speeds, heavy rain, and hailstones – Storms sometimes accompanied by tornadoes |
| Tornado | – Associated with a severe thunderstorm – Violently rotating column of air – Wind speeds range from 65 to 300 mph |
| Microburst / Macroburst | – Associated with a thunderstorm – Powerful downdraft that can cause severe, localized damage |
| Hurricanes | – Highest intensity of a tropical cyclone weather system – Counterclockwise rotation around a center of low pressure – Maintains strength over water – Associated with bands of strong thunderstorms and possibly tornadoes – Well-defined low-pressure center (“eye”) – Sustained winds of 74 mph or greater |
| Nor’easters | – Counterclockwise rotation around a center of low pressure – Forms and maintains strength over either land or water – Often associated with wintry precipitation (snow, sleet, freezing rain) |
Causes of High Winds
New York City is subject to various high-wind events, which each have different characteristics. For the purposes of this profile, high winds are defined as winds exceeding 50-60 mph exceeding 50-60 mph — which aligns with the National Oceanic and Atmospheric Administration’s (NOAA) definition of damaging winds. As nor’easters and hurricanes are discussed in greater detail in the Coastal Storms profile, for the purposes of this hazard profile, high winds are grouped into the three categories below:
Types of High Wind Events
Severe Thunderstorms
Severe thunderstorms, which are capable of producing large hailstones (also known as hail), damaging winds, and tornadoes, can pose serious threats to human life, safety, and property in New York City.
Thunderstorms are normally localized events. According to the National Weather Service (NWS), the average thunderstorm in the United States is 15 miles in diameter and lasts an average of 30 minutes. Non-severe thunderstorms have winds of less than 58 mph and can produce lightning, rain, and sometimes, small hailstones.
About 10 percent of thunderstorms in the United States are classified as severe, with winds of at least 58 mph and/or large hailstones of at least one inch in diameter. Severe thunderstorms happen when warm, moist air collides with colder air. As the warm air rises, the moisture condenses and builds up energy as it forms into a thunderstorm cloud. This pent-up energy releases as a violent thunderstorm. In severe cases, the storm’s structure creates a vertical updraft that can rotate for hours, leading to hazardous tornadoes, high winds, and hailstones.
Hail is made of falling particles of ice. Hail develops as warm, moist air rises in the upper troposphere and cools below the freezing point. The water vapor then condenses into ice crystals. These ice crystals remain suspended by high-velocity updraft winds, growing larger, and eventually fall to the ground as hail, at speeds that can approach 100 mph or more.2NOAA National Severe Storms Laboratory, “Severe Weather 101: Hail Basics,” National Oceanic and Atmospheric Administration.
Generally, the size of hailstones is correlated with the severity of the thunderstorm. In New York City, the diameter of hail typically ranges from 0.20 to 2.0 inches.
Severe storms with high winds lead to several hazards — broken tree limbs, downed power lines, and flying debris, which can lead to power outages, transportation disruptions, damage to buildings and vehicles, and personal injury or death.
Tornadoes
A tornado is a violently rotating column of air that has winds of 65 mph to over 300 mph. These short-lived storms generally appear as whirling funnel-shaped clouds extending from the base of a thundercloud down to the ground. Tornadoes are initially transparent with extremely strong winds — a danger because they cannot be easily seen. As they pick up debris and dust, and as their water vapor condenses, they acquire a grayish color.3Federal Emergency Management Agency, “Tornadoes,” Federal Emergency Management Agency.
Tornadoes are the most violent atmospheric phenomenon to occur over land, and over a small area, they are the most destructive. In a matter of seconds, tornadoes can uproot trees, demolish buildings, and turn harmless objects into deadly missiles. Predicting them can be difficult, so there may only be a few minutes for officials to warn people to seek shelter and take other precautions for their safety.
A tornado’s path of destruction can be more than one mile across and 50 miles long. Each year in the United States, an average of 1,200 tornadoes strike, causing around 60 to 65 fatalities and 1,500 injuries.4U.S. Department of Commerce, A Preparedness Guide: Including Tornado Safety Information for Schools, National Oceanic and Atmospheric Administration.
Non-Thunderstorm High Wind Events
Not all high-wind events are associated with severe thunderstorms and tornadoes. Other types of windstorms that affect New York City are the result of complex interactions in the atmosphere. High winds are a byproduct of certain processes in the air — for example, when atmospheric conditions push air from high- to low-pressure areas, and when strong cold and warm frontal systems interact.
Two other causes of high winds that are familiar to New Yorkers — hurricanes and nor’easters — are included in the Coastal Storms hazard profile.
High winds can create a range of hazards — downed trees and power lines, flying debris, and building collapses. Any of these hazards may lead to power outages, transportation disruptions, damage to buildings and vehicles, and personal injury and death.
Flying debris is the primary cause of damage during a windstorm. Even if a building remains structurally sound, broken window glass can injure people inside and outside the building and allow the wind to cause extensive damage inside.5The National Oceanic and Atmospheric Administration (NOAA) and the Washington State Military Department. Windstorms Brochure.https://web.archive.org/web/20170801174917/www.wrh.noaa.gov/sew/WindstormBro.pdf.
High Wind Attributes/Characteristics
Severity
Depending on the type of high-wind event affecting New York City, NOAA uses two different scales to describe the event. The Enhanced Fujita Scale is used to classify the severity of tornadoes, and the Beaufort Wind Scale is used to classify the intensity of wind speed. Each associates higher numbers on the scale with higher levels of property damage. The size of hailstones and wind gust speeds can also be used to measure the severity of thunderstorms.
Severe Thunderstorms
A severe thunderstorm produces wind gusts of 58 mph or more and/or hailstones of one inch or more in diameter.
Hailstone size varies widely, and the size correlates with the severity of the thunderstorm.
Hail Size and Related Damages
Hail Size and Damage
Tornadoes
Severe thunderstorms can also produce tornadoes. Prior to 2007, NWS used the Fujita Scale (F-Scale) as the standard measurement to rate the strength of a tornado. Since February 1, 2007, NWS uses the Enhanced Fujita Scale (EF-Scale) as its standard measurement.
The EF-scale is more complex than the F-Scale and enables surveyors to assess tornado severity with greater precision. However, the F-Scale is still used to place the more recent high-wind events into the historical context.
NOAA’s chart compares these two scales and indicates the severity of damage associated with these rankings.
Enhanced Fujita Scale
| EF Rating | 3 Second Gust (mph) |
|---|---|
| 0 | 65-85 |
| 1 | 86-110 |
| 2 | 111-135 |
| 3 | 136-165 |
| 4 | 166-200 |
| 5 | Over 200 |
Windstorms
The Beaufort Wind Scale is used to associate observations made during wind events with different levels of wind force and speed.7National Weather Service, “Beaufort Wind Scale,” National Oceanic and Atmospheric Administration.
Beaufort Wind Scale
| Force | Speed | Description | Specifications for use at sea | |
| (mph) | (knots) | Specifications for use on land | ||
| 0 | 0–1 | 0–1 | Calm | Sea like a mirror. |
| Calm; smoke rises vertically. | ||||
| 1 | 1–3 | 1–3 | Light Air | Ripples with the appearance of scales are formed, but without foam crests. |
| Direction of wind shown by smoke drift, but not by wind vanes. | ||||
| 2 | 4–7 | 4–6 | Light Breeze | Small wavelets, still short, but more pronounced. Crests have a glassy appearance and do not break. |
| Wind felt on face; leaves rustle; ordinary vanes moved by wind. | ||||
| 3 | 8–12 | 7–10 | Gentle Breeze | Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered white horses (white caps). |
| Leaves and small twigs in constant motion; wind extends light flag. | ||||
| 4 | 13–18 | 11–16 | Moderate Breeze | Small waves, becoming larger; fairly frequent white horses. |
| Raises dust and loose paper; small branches are moved. | ||||
| 5 | 19–24 | 17–21 | Fresh Breeze | Moderate waves, taking a more pronounced long form; many white horses are formed. |
| Small trees in leaf begin to sway; crested wavelets form on inland waters. | ||||
| 6 | 25–31 | 22–27 | Strong Breeze | Large waves begin to form; the white foam crests are more extensive everywhere. |
| Large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty. | ||||
| 7 | 32–38 | 28–33 | Near Gale | Sea heaps up and white foam from breaking waves begins to blow in streaks along the direction of the wind. |
| Whole trees in motion; inconvenience felt when walking against the wind. | ||||
| 8 | 39–46 | 34–40 | Gale | Moderately high waves of greater length; edges of crests begin to break into spindrift. The foam blows in well-marked streaks along the direction of the wind. |
| Breaks twigs off trees; generally impedes progress. | ||||
| 9 | 47–54 | 41–47 | Severe Gale | High waves. Dense streaks of foam along the direction of the wind. Crests of waves begin to topple, tumble, and roll over. Spray may affect visibility. |
| Slight structural damage occurs (chimney pots and slates removed). | ||||
| 10 | 55–63 | 48–55 | Storm | Very high waves with long overhanging crests. The resulting foam, in great patches, is blown in dense white streaks along the direction of the wind. On the whole, the surface of the sea takes on a white appearance. The tumbling of the sea becomes heavy and shock-like. Visibility affected. |
| Seldom experienced inland; trees uprooted; considerable structural damage occurs. | ||||
| 11 | 64–72 | 56–63 | Violent Storm | Exceptionally high waves (small and medium-size ships might be for a time lost to view behind the waves). The sea is completely covered with long white patches of foam lying along the direction of the wind. Everywhere the edges of the wave crests are blown into froth. Visibility affected. |
| Very rarely experienced; accompanied by widespread damage. | ||||
| 12 | 72–83 | 64–71 | Hurricane | The air is filled with foam and spray. Sea completely white with driving spray; visibility very seriously affected. |
Probability
High winds and severe weather frequently affect New York City. Based on the frequency of these events in the past, the hazards associated with high winds are highly probable in the future.
Severe Thunderstorms
New York City estimates the probability of future high-wind events based upon the annual frequency of past severe thunderstorms. From 2000 to 2022, New York City’s Hazard History and Consequence Database indicates that the city has had 265 thunderstorm events. Of these, 24 events have been classified as producing large hail.
The probability of future severe storms and damaging winds in New York City is high and events at a local scale may happen multiple times each year. By comparison, the recurrence interval for tornadoes and large hail in New York City is much lower.
Tornadoes
Tornadoes in New York City are less common than severe thunderstorms, but they are still likely to occur in the future.
New York City’s first reported tornado was in 1974. Over the past 45 years, seventeen tornadoes appeared in New York City, with at least sixteen ranked at low severity levels of F0 or F1.8Tornado Project, “Tornado Project Online,” Tornado Project.
Reports of tornadoes have increased in New York City over the years. Six tornadoes were reported between 2007 and 2018, compared with only seven reported in the previous 33 years. This increase in reported occurrences may be due to the greater precision of the Enhanced Fujita Scale. Past tornado events have resulted in several injuries, but no fatalities.9New York City Emergency Management, “Hazard History and Consequence Tool,” City of New York.
Non-Thunderstorm Wind Events High Wind Events
Non-thunderstorm high-wind events happen very frequently in New York City — including tropical cyclones, nor’easters, atmospheric conditions forcing air from high- to low-pressure areas, and interactions between strong cold and warm frontal systems.
Based on the historical record, New York City experiences at least one of these high-wind events per year.
Location
New York City is located in an area of the United States that the Federal Emergency Management Agency (FEMA) classifies as susceptible to all types of high-wind events.
FEMA and the National Fire Protection Association’s (NFPA) Model Manufactured Home Installation Standards categorize the United States into four wind zones: Zone I, Zone II, Zone III, and the highest wind zone, Zone IV. These wind zones portray the frequency and strength of extreme windstorms and are used to determine wind provisions for safe installation of manufactured homes.10FEMA, “Wind Zone Comparisons,” in Protecting Manufactured Homes from Floods and Other Hazards: A Multi-Hazard Foundation and Installation Guide, FEMA, 2009.
New York City is located in Zone II, which indicates that it is susceptible to winds in the 90–110 mph range. As noted in the magnified New England detail on the graphic, New York City is also considered to be located in a hurricane-prone region.
In the New York City metropolitan area, no single part of the city is more susceptible to high-wind hazards than another. This assessment is based on the historical record of where high-wind events have occurred.
Thunderstorms and Hail
Thunderstorms occur throughout New York City, but they do not necessarily affect all five boroughs simultaneously or produce high winds or hail that affect every location with the same severity. Some thunderstorms and their associated wind and hailstorms are extremely localized events.
Tornadoes
A common misconception is that tornadoes do not occur in dense urban areas such as New York City. Scientists say that although tornadoes are rare, they could occur in any part of the city.
Since 1950, at least one tornado has occurred in each of the five boroughs, as shown on this map. Note that Manhattan’s August 1995 tornado is not plotted because accurate coordinates for this event are unavailable.
Historical Tornadoes
Source: NYCEM GIS
Historic Occurrences
Between 1974 and 2022, New York experienced many non-thunderstorm high-wind events and severe thunderstorms, which produced damaging wind and tornadoes. Of the 697 events classified as thunderstorms, 195 were recorded as having high winds. Four events produced conditions so hazardous that they received Presidential Disaster Declarations.
On August 3, 2020, Tropical Storm Isaias began to impact New York City, bringing impacts of flash flooding and high winds. During this event, the city experienced up to 28 mph winds, and over 29,000 tree emergencies were reported. In addition, the storm caused power outages to an estimated 289,000 customers, according to Con Edison.11Con Edison Media Relations, “Con Edison Off to a Fast Start on Post-Isaias Restoration,” Con Edison, August 5, 2020.
For more information on high-wind events, use the Hazard History and Consequence Database, an interactive tool developed for this website.
What is the Risk?
High-wind events can damage property and infrastructure, disrupt transportation, down trees and power lines, and cause serious personal injury. New York City’s dense high-rise environment, high number of older buildings, and many open construction sites heighten its vulnerability to dangerous winds.
Social Environment
New York City closely monitors potential high-wind events, but severe thunderstorms and other high-wind events can occur with little or no warning, increasing risks to public safety.
For example, anyone caught outdoors during a severe weather event (such as construction workers, other people who work outdoors, and unhoused people) is more vulnerable to injury and death. People are at risk from injury or death from hailstones, which can fall at speeds faster than 100 mph. Trees can also pose a risk during high-wind events, causing injury or death if they or their branches fall on people or property.
Data on the number of deaths and injuries from high-wind events in New York City demonstrate this risk. From 1996 to 2022, the NWS Storm Events Database records show that there were at least 47 confirmed deaths and 99 injuries during New York City’s 964 severe weather events and lightning strikes.12National Centers for Environmental Information, “Storm Events Database,” National Oceanic and Atmospheric Administration.
If high winds damage property or cause injury, members of vulnerable populations and those with constrained finances are particularly at risk; these populations may not be able to rebound as quickly as other segments of the population.
In addition to potentially injuring people, downed trees can also disrupt utility wires, which can lead to power outages that put people and property at risk. Power outages can disrupt normal activities and increase risk for individuals whose lives depend on a sustained power supply, including people who are on life-sustaining equipment or medical institutions that need refrigeration for medical supplies.
High winds also put the day-to-day operations of New York City, a global hub of commerce and tourism, at risk — closing bridges, disrupting ferry service, delaying flights, and disrupting travel in other ways.
Built Environment
Severe thunderstorms and their associated high winds can cause extreme damage to the built environment. On a national scale, NWS estimates that each year, hail causes more than $1 billion in crop and property damage and that lightning causes more than $1 billion in insured losses.
Locally, the damage to New York City from high winds is also significant. Since 2000, New York City has had three storms in which tornadoes created such extreme damage that FEMA responded by awarding Individual Assistance and Public Assistance grants.13FEMA, “Declared Disasters,” FEMA.
Severe Storm Impact upon New York City (2007 – 2022)14NYCEM, “Hazard History and Consequence Tool,” City of New York.
| Date | Severe Weather Hazards | FEMA Grant Awards |
| September 1, 2021 | Post-Tropical Cyclone Ida, flash flooding, high winds | $135 million in Individual Assistance grants; Public Assistance grants were also available, but the data is still being processed |
| August 4, 2020 | Tropical Storm Isaias, flash flooding, high winds | $4.4 million in Public Assistance across New York State |
| October 29, 2012 | Hurricane Sandy, coastal flooding, high winds | $773 million in Individual Assistance grants; $7.6 billion in Public Assistance grants |
| August 8, 2007 | Severe thunderstorm, heavy rain, high winds, tornado | $7 million in Individual Assistance grants |
A more extensive discussion of the risk and structural vulnerability is available in the Built Environment section of this report.
High winds also pose a serious threat to New York City’s buildings and infrastructure.
Although the 1938 Building Code addressed high-wind loads for skyscrapers and other buildings taller than 100 feet, these older requirements are not as stringent as today’s building codes and may not address higher wind loads for hurricanes. Approximately two-thirds of all New York City buildings were constructed prior to the 1938 code and were designed according to principles that did not explicitly incorporate wind design.
According to Urban Green Council, New York City has approximately 60 older commercial high-rise buildings constructed in accordance with the 1938 code that still stand. Although they were built according to the design requirements of the 1938 code, their modernist glass and metal envelopes could still be at risk during high-wind events.
Facade elements of historic buildings are also at risk during high-wind events, particularly six-story masonry structures with poorly maintained masonry parapets and cornices. Street facades on typical brownstones are also vulnerable because these types of buildings are often poorly attached to the party walls, risking a collapse during a high-wind event. If the street facades do collapse, pedestrians below are at high risk. Potentially fatal injuries can occur if cladding is not securely attached and components — such as parapets, cornices, lintels, and roof coverings — fall to the street level below.
In addition to the age of a building, certain types of building construction are more structurally vulnerable. For example, steel and concrete structures are engineered structures and as such are more resistant to high winds, compared to empirically built, wood-frame structures, which are at greater risk. In New York City, close to 70 percent of all buildings are wood-frame structures. Among the boroughs, Staten Island has the highest percentage of wood-frame buildings. With 92 percent of its structures made of wood, Staten Island’s built environment is highly vulnerable to damage caused by windstorms and tornadoes.
Temporary installations on construction sites and partially completed buildings are highly vulnerable to high winds. At New York City’s many construction sites, tools, construction materials, cranes, scaffolding, derricks, concrete formwork, sidewalk bridges, and other items can become airborne or unstable during high-wind events. High winds affect partially completed facades and structural frames differently than when these components are incorporated within finished buildings.
In New York City’s dense urban environment, flying debris poses a substantial risk. Window glass that breaks during high winds can damage a building’s contents and cause injuries inside and out. Windows and doors that fail, are broken, or are blown wide open due to high wind can greatly increase storm damage.
Some older buildings in New York City use loose stone, aggregate, or gravel as roof covering. These materials can become dangerous projectiles during a high-wind event, injuring people and damaging surrounding buildings.
Risk in New York City is exacerbated by the “urban canyon effect.” This phenomenon can modify the speed and direction of winds in cities with high concentrations of tall buildings, and relatively narrow streets such as Midtown Manhattan, the Financial District, and downtown Brooklyn. Large buildings in these areas are not at risk because they are designed to withstand hurricanes. However, smaller buildings in these neighborhoods can be at greater risk of damage because they may not be specifically designed to accommodate the increased wind speeds and resulting higher wind loads.
Natural Environment
High-wind events can negatively affect the natural environment by destroying trees, damaging the aesthetics of parks and open spaces, and impacting New York City’s waterways.
Thunderstorms may also have secondary impacts on the city’s natural environment such as lightning-induced fires and hazardous material spills or leaks. The latter may occur due to torrential rains mixing with hazardous materials if such materials are not properly contained.
A more extensive discussion of the risk to New York City’s natural environment from high winds is included in the hazard profile on flooding.
Future Environment
Predicting the impact of high-wind events on the future environment is complex and varies by the type of weather event. Some of the impacts of climate change are warmer weather and moister air, which can create an environment favorable for severe thunderstorms, nor’easters, and tropical cyclones, but there may be unforeseen impacts that could limit the frequency of these events. At this point, it is unclear how the long-term effects of climate change will impact the strength and occurrence of high-wind events.
How to Manage the Risk?
Many strategies can be employed to protect people, property, infrastructure, and the environment from the impacts of extreme weather. What follows are a few examples of their application in New York City.
New York City’s approach to risk management:
Regulatory Controls to Strengthen Buildings
New York City’s immense, dense building stock constitutes such a significant risk exposure that this section begins by focusing upon risk-mitigation actions to strengthen buildings.
NYC Construction Codes
Since 2008, New York City Construction Codes have included provisions requiring that new buildings be able to withstand high winds in a dense, high-rise environment.
The Building Code, a component of New York City Construction Codes, contains wind-exposure categories that establish design requirements for location, surroundings, and occupancy, so that all new buildings can withstand high winds. For example, buildings along the coastline and buildings taller than 300 feet are subject to higher wind load requirements.
The Building Code also requires that New York City buildings be designed to resist high-wind events. Severe thunderstorms, nor’easters, and other non-thunderstorm high-wind events occur in New York City more frequently than hurricanes. Due to concern about hurricane-force winds, buildings here are designed to withstand higher pressures than most of the strong wind events experienced in the city. The Building Code also contains wind-resistance criteria for certain building components and facade systems.
New York City’s Construction Codes specify design standards that minimize risk from hurricane-level winds that are most likely to occur in the eastern part of the United States. The standards also contain provisions to mitigate risks from the unique wind hazards associated with a dense, high-rise environment. New buildings and older buildings that are undergoing major renovations are required to meet these standards.
New Buildings
New buildings are designed and constructed so that they are able to resist high-wind events — this includes the building structure and envelope.
Structural engineers use highly refined methods to analyze how buildings and structures respond to wind loads. Most of the wind loads on high rises in New York City are evaluated using wind tunnel testing. Wind tunnel testing uses small-scale models of the built environment and simulates various levels of wind conditions. The structures are designed with highly sophisticated computer programs that not only provide for the building’s resistance to wind, but also account for the comfort of occupants during high-wind events.
Retrofitting Existing Buildings
Older buildings can be retrofitted to withstand high-wind loads.15National Wind Institute, “Protection from Extreme Wind,” Texas Tech University. Recommended measures include:
- Strengthening the connections of a building’s structural components by anchoring a wooden building to its foundations and by anchoring its roof frame to load-bearing walls.
- Replacing unreinforced brick masonry parapets with reinforced masonry parapets that are securely anchored to the rest of the building.
- Replacing roof coverings with larger pavers to meet code standards to reduce the risk of the pavers being blown off.
- Installing windows that are rated by the American Architectural Manufacturers Association (AAMA).
- Installing window shutters.
- Reinforcing and securing rooftop equipment, such as heating, ventilation, and air-conditioning units.
Maintenance and Repairs
Protecting our existing building stock requires inspection, maintenance, and repair of structural weaknesses.
Maintaining Older Buildings
For buildings whose construction predates the 1968 Building Code, maintenance is particularly important to lower the risk of damage from high winds. Measures include:
- Keeping roofs tight and in good condition.
- Inspecting the wood regularly to identify rot.
- Securing cornices.
- Repointing mortar regularly and fixing cracks, especially on chimneys and parapets.
- Replacing any glass that is not rated for New York City winds. For buildings under 100 feet high, the standard is 30 pounds per square foot.
- Making sure that all windows and doors (and any other opening) can be shut completely whenever high winds are predicted.
The New York City Department of Buildings (DOB) Facade Safety Inspection Program reduces risk from high winds by identifying the need to make repairs and to protect buildings on a regular basis. The program requires owners of buildings taller than six stories to have exterior walls and appurtenances inspected once every five years and to file a technical report with the DOB.
Mitigating Hail Damage
Retrofitting and design strategies can also be used to minimize damage caused by hailstones. These measures include:
- Installing structural bracing, shutters, and laminated glass in windowpanes, and including hail-resistant roof coverings or flashing in the building design to minimize damage.
- Obtaining information from the Insurance Institute for Business and Home Safety (IBHS) about the most appropriate type of roof covering for the New York City region.
- Improving roof sheathing to prevent hail penetration.
Research Initiatives
Research on the following topics informs revisions to the New York City Construction Codes:
- How high winds impact different building types, partially completed buildings, and construction sites.
- The new standard referenced for wind in the 2022 New York City Building Code addresses roofing and wind resistance, specifically the section SBCCI SSTD 11.
- How a building’s age, construction, materials, and height affect its vulnerability to structural damage from high winds.
The New York City Mayor’s Office of Climate and Environmental Justice (MOCEJ), in consultation with DOB, was required by Local Law 81 of 2013 to complete a report to analyze the impact of high winds on certain at-risk buildings. The study, which was completed in 2021, served to confirm that the existing codes were sufficient.
Environmental Controls
New York City’s trees are exceptionally vulnerable during high winds. High winds could cause large tree limbs to fall or entire trees to topple. Pruning trees and implementing appropriate tree maintenance strategies can help reduce this risk. The New York City Department of Parks and Recreation (NYC Parks) oversees block pruning and commitment-pruning programs, in which they prune street trees on a neighborhood-by-neighborhood basis, allowing for the department to prune a portion of street trees in each community board every year. Commitment pruning deals with emergency situations such as tree limbs obscuring traffic signals. The division also prunes trees in parks.
A similar program is Con Edison’s vegetation maintenance program, which trims branches near power lines along rights-of-way. This initiative also removes damaged or unhealthy trees and vegetation to create safe minimum cleared distances between power lines and the surrounding trees. Every three years, Con Edison returns to trim back growth and to reestablish the minimum clearance.
Promoting Preparedness
Public Warnings and Alerts
When dangerous weather conditions threaten the area, New York City monitors and disseminates information it receives from NWS and other sources. The NWS Storm Prediction Center (SPC) issues a Severe Thunderstorm Watch whenever a large, multistate area is at risk, providing a few hours’ notice in which people can take necessary precautions against wind and rain hazards. The NWS SPC issues a Severe Thunderstorm Warning either during the storm or very soon before it is expected to occur. The timing of this warning can range from a few minutes to an hour ahead of the danger.
Because damaging winds can arrive suddenly, New Yorkers need to be prepared ahead of time to respond to alerts such as a Severe Thunderstorm Warning. New York City’s communication strategies include:
- Using multiple channels, including Notify NYC, press releases, websites, and social media, to issue emergency alerts regarding forecasted severe thunderstorms or other high-wind events.
- New York City Emergency Management (NYCEM) reaches vulnerable populations by working with our community partners, including our Strengthening Communities program, who amplify and share messaging with community groups. During severe weather, NYCEM may activate the Advance Warning System, which messages organizations that specifically work with individuals with disabilities, and may partner with organizations like the New York City Department of Social Services (DSS) to conduct expanded outreach to vulnerable populations, including unhoused individuals.
- Notify NYC is the City’s official source of information about emergency situations and is used prior to and during high-wind events. NYCEM sends Notify NYC notifications and alerts swiftly to over more than 11 million subscribers in 14 languages, including American Sign Language.
Construction Site and Property Alerts
Another important communication strategy to reduce the risk of high-wind hazards is sending weather advisory notifications to property owners, contractors, and developers. These notifications alert this community to specific preventive actions that they can take quickly, such as removing loose construction materials from sites and securing loose items that could become airborne in high winds.
DOB offers building owners the option of subscribing to receive weather advisories. DOB issues Inclement Weather Advisories to property owners, builders, and contractors, which include advice on precautions to take to prepare for high winds at their properties. The DOB Preparing Sites for Extreme Weather Guide provides more detailed instructions on how to secure buildings and sites prior to a high-wind event. To enforce safety, violation notices are issued when construction sites are not safely secured.
Public Education
Longer-term education efforts help New Yorkers to prepare for and respond to hazards from high winds. Helpful messages include:
- People should know the safest places to take cover inside a building ahead of a tornado or other high-wind emergency.
- Furniture on porches, balconies, and other outdoors places, and other loose items, should immediately be secured.
- Building owners and residents should have emergency action plans that define procedures to be followed if a building-related incident or emergency happens.
NYCEM’s Ready New York: My Emergency Plan provides information on how households can prepare to stay safe during severe weather events like severe winds.
Based on the Ready New York campaign, Ready NYC is a mobile application that allows users to make an emergency plan. It is available in Apple iOS and Android versions.
Additionally, NYCEM’s Strengthening Communities program offers grants to community networks to build their emergency preparedness plan and support local community resources. The training program focuses on five key areas/deliverables to build an emergency plan specific to a community: creating a needs assessment; designing community maps of the area where services are provided; building a resource directory; preparing a communication strategy; and creating donations and volunteer management plans. NYCEM staff provide training, coaching sessions, and tools that guide participating networks through the program.
The NYCEM Reduce Your Risk guide explains to New Yorkers, and in particular to homeowners, how to reduce risks posed by tornadoes and other strong windstorms. Advice includes performing routine building maintenance, inspecting buildings for structural weaknesses, and making needed repairs.