USGS Hurricane Response Met Challenges in 2017, Prepares for 2018
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 2018, the NOAA forecast calls for 10 to 16 named storms, including five to nine hurricanes and one to four major hurricanes.
The forecast comes in the wake of the challenging 2017 hurricane season, when the USGS mounted a months-long effort to gather scientific information that helped protect lives and property. Not long after Hurricane Nate—the last hurricane of 2017 to make a U.S. landfall—disintegrated over Alabama on October 8, the agency’s coastal storm-response leaders began preparing for the 2018 season.
“The USGS’ response to five major hurricanes in 2017 was impressive,” said Jim Reilly, who was sworn in as director of the USGS on May 14. “USGS employees demonstrated their scientific expertise, creative problem-solving skills, and dedication. We are all hoping for a calmer 2018, but if it isn’t, we’ll be ready to provide the best possible science to local, state and federal officials and local residents. We will, as always, be ready to provide the data allowing the best possible decisions on response and recovery and to continue the ongoing effort to make communities safer and more resilient.”
The USGS is phasing in innovations to make its hurricane response even more effective this year, said Athena Clark, the USGS science advisor for the Southeast Region and the bureau’s Coastal Storm Response Team leader.
“We work throughout the year in anticipation of hurricane season,” Clark said. “We are constantly working to hone our skills and improve technology, with the goal that every time we respond to a storm, the results get better and better.”
2017 Records Set and Challenges Met
With 17 named storms, the 2017 season was the most active since 2005 and the seventh most active on record, based on preliminary measurements of the combined strength and duration of the year’s tropical storms and hurricanes. The 2017 season saw about 350 USGS scientists and staff respond to five major hurricanes that affected the U.S. mainland and islands. For two solid months, USGS crews were in the field daily in storm-threatened or storm-ravaged parts of the country, from Texas to Massachusetts, and in Puerto Rico and the U.S. Virgin Islands. USGS crews made more than 400 special measurements of river and stream flow, collected evidence of floodwater height and extent at 1,939 sites, and documented more than 75 instances when hurricane-swollen rivers and streams reached the highest water levels on record for those sites.
In the days before Hurricanes Harvey, Irma, Jose, Maria, and Nate were predicted to make landfall, USGS hydrologists deployed water-level and weather-measuring instruments that are vital to coastal storm surge, erosion, and flooding forecasts. As soon as each storm passed, crews fanned out to document high-water events, and to take measurements of rivers overflowing their banks and reservoirs overfilled by record-breaking rain—work that helps emergency officials successfully manage potentially deadly floodwaters.
Coastal erosion experts posted 25 separate forecasts identifying where beaches along the Atlantic and Gulf coasts were at risk of dune erosion, overwashing or inundation. And after Hurricane Maria devastated Puerto Rico, USGS landslide experts traveled more than 600 miles overland across the island’s mountains and conducted helicopter surveys to assess the extent and effects of landslides. Meanwhile, geospatial scientists marshalled USGS data-gathering and mapping expertise to provide the National Guard and other first responders with maps packed with information about the island’s topography and infrastructure.
“USGS’ response to those five hurricanes was phenomenal,” Clark said. “Our agency and our employees were taxed, but people in other government agencies and the public could see that we were able to rise to the occasion.”
The agency is ready to do so again, Clark said. Here is the process that will unfold if a major hurricane threatens a landfall on the U.S. coast, or if especially vulnerable resources or areas lie in a weaker storm’s forecast path.
2018: Preparing for a Landfall
To prepare for landfall of a major storm, USGS crews deploy in advance to position special storm-tide sensors that can measure the height, extent, and timing of the tide pushed ashore by the hurricane. The storm-tide sensors, housed in vented steel pipes a few inches wide and about a foot long, are part of the USGS Storm Tide Monitoring Network.
Designed for quick installation on bridges, piers, and other structures that have a good chance of surviving a hurricane, they collect water-pressure readings that help define the depth and duration of a storm tide, the time it arrives, and its retreat. That information helps officials assess storm damage, tell the difference between wind and flood damage, and improve computer models for forecasting effects of future storms.
New Sites Will Provide New Insights
This year, for the first time, those storm-tide sensors will be deployed to sites that have been selected at the start of the season, along the coast from the Carolinas to Texas. Based on a similar network of sites put in place in the mid-Atlantic and Northeast after Hurricane Sandy, the Southeast and Gulf Coast sites were chosen in part for their ability to withstand a storm and in part because wherever storm-tide sensors have been placed in the past, new data from those sites are especially valuable.
“It’s critical to be able to monitor at the same locations for different hurricanes,” Clark said. “Being able to see the difference in impact between a Category 1 and a Category 5 is valuable information that can improve our ability to predict what future storm tides will do.”
Some of the permanently designated sites “are strung like pearls along the coast” roughly five miles apart, Clark said. Others are set in straight lines or transects running inland so they can record how the storm tide changes as it moves away from shore.
The team also decides whether to supplement flood information from the USGS network of more than 8,200 permanent stream gauges by setting out specially designed rapid-deployment gauges in areas where flooding is likely, but no gauge is already in place. Data from the stream-gauge network helps the National Weather Service develop flood forecasts, the U.S. Army Corps of Engineers make flood control decisions, and local agencies plan their emergency response.
Forecasting Coastal Change
Research scientists at the USGS St. Petersburg Coastal and Marine Science Center have developed a sophisticated computer model that provides detailed predictions of likely effects of a hurricane on sand dunes and other coastal features. The coastal change hazard forecast model covers the Atlantic and Gulf Coast regions where storm effects are expected, making predictions at one-kilometer intervals. Its forecasts predict 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.
The forecasts can help emergency managers decide which areas to evacuate, which roads to use, and where to position equipment for post-storm clean-up. The forecasts begin 48 hours before a storm is expected to make landfall, are updated based on the latest forecasts from the National Hurricane Center, and are available to the public at the USGS Coastal Change Hazards Portal.
Working with the National Weather Service, the St. Petersburg-based team has also developed a forecast viewer that is updated several times a day, with real-time water levels from the weather service’s Nearshore Wave Prediction System. The Total Water Level and Coastal Change Forecast Viewer currently covers selected areas from Florida through Maine, totaling about 1,865 miles (3,000 kilometers) of coastline. Ultimately it will include the entire U.S. coastline. The viewer predicts the timing and magnitude of water levels at the shoreline, as well as potential impacts to coastal dunes. NOAA will use the viewer’s predictions to help inform forecasters at the National Hurricane Center, and will also make the predictions available to meteorologists at selected National Weather Service forecasting offices.
During the Storm: Monitoring Floods
Hurricane rains can cause flooding far inland from the coast. To track inland flooding, the USGS gathers data from its network of stream gauges, as well as from rapid-deployment gauges. When flooding is occurring, USGS field crews make real-time streamflow measurements to verify the stream gauge readings. The crews also quickly replace storm-damaged or lost gauges. During and right after hurricane flooding, these records help the Federal Emergency Management Agency (FEMA) target emergency relief to the hardest-hit areas. You can track storm-surge sensor deployment on the USGS Flood Event Viewer and see stream gauge readings in real time on the USGS National Water Information System.
Creating Maps and Apps That Show the Big Picture
The USGS Earth Resources Observation and Science Center located in Sioux Falls, South Dakota, provides disaster-response agencies with remotely sensed imagery and other geospatial data that can be shared through a common delivery portal, the USGS Hazards Data Distribution System. The Geospatial Information Response Team, a mapping and remote-sensing group, coordinates, archives, and distributes key pieces of information, such as the storm track, lidar elevation data, detailed local maps, and information gathered in the storm or flood response effort. They also work with USGS and partner scientists to provide useful information for understanding and managing storm situations, and make this information available online.
In 2017 the team worked with the National Geospatial Technical Operations Center to quickly produce special-edition maps of Puerto Rico for first responders after Hurricane Maria devastated the island. These were custom-printed at 1:250,000-scale to show the entire island and were based on the USGS The National Map. They included essential information for first responders such as place names, water bodies, elevation contours, and transportation networks. US Topo maps, produced nationwide at a scale of 1:24,000 and maintained on a 3-year schedule, were also printed and distributed to first responders for the 2017 hurricane season. Maps derived from The National Map “are the only high-quality, consistent, nationally standardized map series available that can be used to support disaster response,” said Lance Clampitt, emergency response coordinator for the National Geospatial Program. The team is ready to produce similar maps during the 2018 season.
After the Storm: Repairing, Recovering, Recording Effects
As soon as it is safe to do so, USGS crews head into the field in flood-impacted areas to determine and document the extent of flooding. They do this by making in-the-field observations of water heights and flows, and by flagging and surveying high-water marks on buildings, bridges, embankments, and trees. High-water marks are seeds and other debris left behind by floodwaters, recording their extent and depth. FEMA uses this and related information to steer relief to areas of greatest need.
After hurricanes, crews typically must repair or replace some storm-damaged, lost, or destroyed gauges. Wherever flooding occurred that went unmeasured because of a lost or damaged stream gauge, the crews develop indirect measurements of the water flow, using the highest high-water mark at that site. A computer model uses detailed information about the shape, depth, and geology of the stream, along with information about 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 mark.
After a hurricane strike on a U.S. sandy shoreline, the Coastal Change Hazards storm team uses NOAA satellite imagery to assess the impact of storm surge and waves. These NOAA images document changes to the coast after the storm, helping the USGS fine-tune its coastal change forecasting model. In 2017 the hazards team conducted pre- and post-storm photo comparisons for Hurricanes Harvey, Irma, and Nate. The team also collected lidar data along Florida beaches affected by Hurricane Irma, combining that information with some ground and drone surveys and high-angle oblique photos provided by NOAA to study storm-related changes to Florida beaches in detail.
The USGS is even prepared to help land managers cope with one of the unexpected consequences of hurricane-related flooding: the spread of non-native aquatic species carried along by floodwaters into areas they normally cannot reach. Some non-native plants and animals have the potential to become invasive, out-competing native species and causing them to disappear. Others can inflict physical damage on vulnerable ecosystems. After a hurricane, land managers coping with a range of issues are hard-pressed to track down and control these incursions.
In a pioneering effort in 2017, the USGS Non-Indigenous Aquatic Species Program developed special sets of searchable maps showing the areas that were flooded by Hurricanes Harvey, Irma, Maria, and Nate, and the non-native species that could potentially have been spread by each storm’s floodwaters. The maps allow land managers to narrow down areas of potential non-native species introductions and plan early campaigns to control their spread. The U.S. Fish and Wildlife Service has used them at some national wildlife refuges where hurricane floodwaters spread in 2017, and scientists with the Non-Indigenous Aquatic Species Program plan to produce similar maps, if needed, in 2018.
Recovering and Rebuilding
Meanwhile, the work of repairing and rebuilding in the aftermath of 2017 continues. Congress has appropriated about $37 million for hurricane-related expenditures in Puerto Rico, Florida, and other parts of the U.S. affected by hurricane strikes in 2017. The money allocated to the USGS includes funding for several projects to restore scientific infrastructure that was damaged by Hurricanes Irma and Maria in Puerto Rico, such as stream gauges, earthquake-monitoring instruments, and coral reef research equipment. The appropriation also is supporting scientific fieldwork that will factor in the dramatic changes made to many streams, rivers, and mountainsides. Based on those field observations and new data collected by new or repaired instruments, scientists will be able to develop updated flood and landslide predictions.
In Puerto Rico, the U.S. Virgin Islands, and on the mainland, the funding will pay for highly accurate coastal elevation data, based on lidar images and other sources. The lidar data, most of which will be available in 2019, will improve the USGS capacity to predict coastal erosion in future years.
While the USGS is readying 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.
in this issue:
USGS Hurricane Response Met Challenges in 2017, Prepares for 2018