This year is projected to have a 40 percent chance of being a near-normal season and a 30 percent chance of being above normal, according to the National Oceanic and Atmospheric Administration Climate Prediction Center’s 2019 hurricane season forecast. An average hurricane season produces 12 named storms with winds of 39 miles per hour or higher, including six hurricanes and three major hurricanes of Category 3, 4 or 5. For 2019, the NOAA forecast calls for nine to 15 named storms, including four to eight hurricanes and two to four major hurricanes.

Tropical storms, hurricanes and other large coastal storms can impact coastal and inland communities and ecosystems with high winds, storm surge, erosion and flooding. These forces can destroy buildings, roads and bridges and reshape the nation’s coastline.

When a major storm threatens to make landfall in the United States or its territories, the USGS provides comprehensive scientific capabilities and information that decision makers, emergency responders and communities can use to help them prepare, cope and recover from a storm. This includes the USGS’ ability to forecast coastal change; track storm surge, river and stream levels and flow; measure coastal and inland flooding across entire regions; capture high-resolution ground elevation and topographic data; and create detailed maps used by disaster teams responding in the aftermath of storms.

Forecasting Coastal Change as a Hurricane Approaches

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Before a storm’s expected landfall, USGS coastal change experts forecast how a storm may reshape the coastline using a sophisticated system they developed called the coastal change hazard forecast model.

The model provides detailed forecasts of a strong storm’s likely effects on sandy shorelines along the Atlantic and Gulf coasts. It predicts where protective sand dunes are likely to be eroded at their bases or overtopped by storm waves and where coastal areas behind the dunes could be inundated by seawater.

These forecasts can help emergency managers make critical decisions before a major storm strikes, including which areas to evacuate, which roads to use and where to position storm cleanup equipment. The forecasts typically begin 72 hours before a storm is expected to make landfall, are updated based on the latest forecasts from the National Hurricane Center and are available at the USGS Coastal Change Hazards Portal.

Working with the National Weather Service, the coastal hazards storm team also updates forecasts for some areas several times a day using real-time water levels from the Weather Service’s Nearshore Wave Prediction System. The team’s Total Water Level and Coastal Change Forecast Viewer displays results from a new model that currently covers about 1,865 miles of coastline in select areas from Florida through Maine. The model predicts the timing and height of water levels at the shoreline, as well as potential impacts to coastal dunes. This year, NOAA will use the predictions to help inform forecasters at the National Hurricane Center. As the program's coverage area expands, the predictions will also be made available to National Weather Service forecasting offices and to the public.

“We are working to expand the viewer to include the entire Atlantic and Gulf coasts and hope to accomplish that by early fall,” said research oceanographer Kara Doran, USGS Coastal Change Hazards Storm Team leader. “We are also updating our main forecast model, adding information that shows how some beaches’ topography has been changed by recent hurricanes and other events. This ensures our forecasts are based on the most accurate information available.”

Measuring and Monitoring the Storm

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Once it’s determined a hurricane or tropical storm will likely strike somewhere in the U.S., USGS field crews deploy to the storm’s projected path along the coast to install special water-level measuring instruments called storm-tide sensors. These sensors record data that track storm tides and coastal flooding. This information helps USGS and NOAA scientists improve certain forecast models. It also helps FEMA and other federal, state and local agencies’ relief efforts by pinpointing the areas hardest hit by storm-tide flooding.

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Storm-tide sensor information can also help engineers design structures to better withstand floods and assess how well engineered dunes and wetlands reduce storm damage. It can help inform land-use practices and building codes and help lead to more resilient coastal communities.

USGS crews also install rapid-deployment gauges at locations that are not monitored year-round, but are at risk of flooding due to an approaching storm. These RDGs provide real-time information to emergency managers tracking floodwaters, such as water level, precipitation, wind speed, humidity and barometric pressure.

RDGs can be quickly installed at critical locations when needed, which helps augment the USGS’ nationwide real-time network of about 8,500 streamgages that transmit both streamflow and water levels and another 1,700 streamgages that transmit only water levels. The National Weather Service uses data from streamgages that provide both water level and streamflow to develop flood forecasts, and the U.S. Army Corps of Engineers use these data to make flood-control decisions. The streamgages that provide only water levels are used by local agencies to track flood locations and plan emergency response and allow the public to monitor local rivers and stream levels in real time.

You can track storm-tide sensor and RDG deployments and view past storms on the USGS Flood Event Viewer and see USGS streamgage readings in real time on both the viewer and the USGS National Water Information System.

Expanding the USGS Permanent Storm-Tide Sensor Network

The USGS’ permanent storm-tide sensor network runs along the Atlantic coast from Maine to South Carolina and along the Gulf of Mexico from Texas to the Florida Keys.

This network consists of hundreds of pre-installed storm-tide sensor brackets that are precisely surveyed so that their GPS locations and elevations are known. Field crews can quickly install storm-tide sensors in the brackets as a major coastal storm approaches and can recover the sensors after the storm has passed. This saves time and gets the sensors’ recorded information to emergency managers and scientists within days of a hurricane or tropical storm strike.

This year, the USGS plans to expand the permanent storm-tide sensor network to include Hawaii and parts of the Pacific coastline from Washington State to California. USGS crews will likely work through the summer to install the brackets at selected sites.

The decision to expand the network was made after last year’s busy Pacific hurricane season, when Hurricane Lane became the first hurricane to hit Hawaii since 1992 and a weakened Hurricane Olivia became the first tropical cyclone in modern records to hit the islands of Maui and Lanai.

Determining the Extent of Flooding

Once the storm danger has passed, USGS field crews travel to the affected areas to make real-time streamflow measurements, verify the accuracy of streamgage readings and quickly repair or replace damaged or lost gauges. This work is vital to flood forecasting and informs decisions on how best to protect communities.

The crews also fan out across affected areas to document high water. They look for telltale lines of seeds, leaves, grass blades and other debris left behind on tree trunks, buildings, bridges and other structures as floodwaters recede. Once they find these high-water marks, they photograph and record details about them and survey them to determine the depth and range of the flooding. This field work is time-sensitive, because high-water marks can be destroyed by weather and property owners’ cleanup efforts. FEMA uses high-water mark data and related information to steer relief to areas of greatest need in the days after a storm, and later, to update flood insurance maps.

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Wherever flooding went unmeasured, the crews develop indirect measurements of the water’s flow using the high-water marks at that site. A computer model uses detailed information about the stream’s shape, depth and geology, along with records of past floods at that site, to determine how much water flow it would take to create a flood matching the one recorded by the high-water marks.

In order to analyze the data gathered in the field after a storm, USGS scientists need accurate, detailed information about land elevation, which is provided by the USGS 3D Elevation Program. That program collects data using lidar - a technique that uses light pulses to produce high resolution elevation imagery - over the United States and its territories. These data are used for mapping storms’ flood inundation, modeling storm surge, evaluating topographic changes like beach and dune erosion and pinpointing damage to buildings and other infrastructure. Up-to-date elevation data are also essential for supporting infrastructure repair and redevelopment after a storm.

The USGS 3D Elevation Program acquires this data across the country and makes it publicly available on The National Map.

Creating Maps and Apps for Hurricane Response

During a disaster like a hurricane, first responders often rely on the USGS National Geospatial Program, which collects, archives and shares digital records on the nation’s topography, natural landscape and human-made environment. The program’s Geospatial Information Response Team (GIRT) works within the USGS and with partner agencies to provide key information to federal, state and local agencies, emergency managers and first responders. The information is shown on multi-layered websites or on printed maps that provide a big-picture view of a storm’s impacts, or a close-up of a specific community.

This hurricane season, the team may add more features to the website and printed maps prepared after individual storms, said USGS physical scientist Lance Clampitt, the GIRT chairman. “For example, we could highlight a specific transportation corridor that may be impassable, or cultural features from the National Register of Historic Places database.” The goal, Clampitt said, is “to give disaster response teams additional information about the area.”

Hurricane Preparedness Resources

While the USGS is prepared for the coming season, people potentially in the path of hurricanes can prepare as well by going to ready.gov or listo.gov for advice on what steps they can take to protect lives and property.

For more information please visit these additional websites:

Ready.gov for children— What to do before, during and after a hurricane

 USGS Coastal Change Hazards: Hurricanes and Extreme Storms – Information on coastal change

USGS Flood Information—Information about current and past flooding

USGS WaterAlert – Sends email or text messages from the USGS streamgage of your choice

USGS WaterWatch— Provides current USGS water data for the nation

NOAA’s National Hurricane Center