Flood and Storm Tracker (FaST) Maps

These maps were created to help assess impacts on nonindigenous aquatic species distributions due to flooding associated with storms. Storm surge and flood events can assist expansion and distribution of nonindigenous aquatic species through connection of adjacent watersheds, backflow of water upstream of impoundments, increased downstream flow, and/or creation of freshwater bridges along coastal regions. These maps will help natural resource managers determine potential new locations for individual species, or to develop a watchlist of potential new species within a watershed.

PDF One Pager NAS FaST

Initial FaST Maps are generated within days of a storm. How we do this.

Revised FaST Maps are generated once actual flooding data becomes available. How we do this.

Final FaST Maps are generated one year after a storm. How we do this.

Historic FaST Maps are generated for select storm and flood events prior to 2017. How we do this.

Disclaimer: This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.



Hurricane Idalia (North) - Initial map

South Atlantic Coast
August 30, 2023 - September 1, 2023
Hurricane Idalia (North)

Hurricane Idalia (South) - Initial map

Florida Gulf Coast
August 29 - 31, 2023
Hurricane Idalia (South)


Hurricane Ian - Final map

Peninsular Florida and South Atlantic Coast
September 24, 2022 - October 8, 2022
Hurricane Ian


Hurricane Ida (North) - Final map

North Atlantic Coast
September 1 – 3, 2021
Hurricane Ida (North)

Hurricane Ida (South) - Final map

Eastern Louisiana and Mississippi Gulf Coast
August 27 – September 3, 2021
Hurricane Ida (South)


Hurricane Delta - Final map

Louisiana and Texas Gulf Coast
October 6, 2020 – October 13, 2020
Hurricane Delta

Hurricane Sally - Final map

Gulf and South Atlantic
September 13, 2020 - September 20, 2020
Hurricane Sally

Hurricane Isaias - Final map

Mid-Atlantic Coast
July 31, 2020 - August 7, 2020
Hurricane Isaias


Hurricane Dorian - Final map

South Atlantic Coast
August 28, 2019 - September 7, 2019
Hurricane Dorian

Midwest Spring Flood - Final map

Upper Mississippi River Basin
March 1, 2019 - May 31, 2019
Central US Flooding


Hurricane Michael - Final map

Florida Panhandle
October 8, 2018 - October 15, 2018
Hurricane Michael

Hurricane Florence - Final map

The Carolinas
September 7, 2018 - October 7, 2018
Hurricane Florence

Hurricane Lane - Final map

Hawaiian Islands
August 22, 2018 - September 15, 2018
Hurricane Lane


Hurricane Nate - Final map

Eastern Gulf Coast states
October 5, 2017 - October 14, 2017
Hurricane Nate

Hurricane Maria - Final map

Island of Puerto Rico
September 16, 2017 - October 3, 2017
Hurricane Maria

Hurricane Irma - Final map

Peninsular Florida and Atlantic coast of Georgia and South Carolina
September 3, 2017 - September 30, 2017
Hurricane Irma

Hurricane Harvey - Final map

Gulf coast of east Texas and western Louisiana
August 24, 2017 - September 24, 2017
Hurricane Harvey


Hurricane Sandy - Historic map

North Atlantic Coast
October 21, 2012 - October 30, 2012
Hurricane Sandy

Hurricane images courtesy of NASA and NOAA

The initial USGS NAS FaST maps are created within 2-3 days of an event to quickly identify flooded 10-digit hydrologic units (HUC-10s) based on USGS Water Science Centers stream gages or storm tide sensors with water heights at or above flood stage. This map integrates flooded hydrologic units with known locations of established, or possibly established, introduced aquatic species. All hydrologic units surrounding known locations of introduced species are included as possible areas of infestation, until actual hydrologic connections have been determined (step 2, revised maps). The NAS FaST map identifies both the established species within a hydrologic unit and the potential species for new introductions (defined as established species in adjacent watersheds) due to flooding impacts.

The refined NAS FaST map enhancement provides information only on the locations with flooding conditions that could breach drainage divides. We utilize information on the relative flood height using the best available data from the USGS Water Science Centers including stream gages, storm surge gages, inundation maps (when available), and identified high water marks along with National Oceanic and Atmospheric Administration modeled storm surge. This information is combined with information on the elevation of the hydrologic units at the 10-digit level (HUC-10s) boundaries (drainage divides) identified from digital elevation models. The flood elevation data was mapped with the hydrologic units' drainage divide elevations to determine if the flooding conditions were of sufficient height to breach the boundary. These "connection points" are identified along the hydrologic units' boundaries. Drainage divide connections determined by upstream stream gages at flood stages were assumed connected along streams and not given connection points on the map.

Hydrologic units identified as being flooded and potentially connected as part of the refined NAS FaST map are established based on the best available data. This map may not include all flooded areas. The refined NAS FaST map focuses on the potential spread of nonindigenous aquatic species between hydrologic units and is not a map of flood inundation.

The final NAS FaST map enhancement includes information on flood connections at drainage divides and pre-storm species observations from the revised map with the addition of post-storm species observations approximately one year after the storm event. We map NAS specimens collected within a year after the storm event inside 10-digit hydrologic units (HUC-10s) where species were previously designated as potentially spread due to flooding in the revised map. We assume a potential pathway due to flooding based on best available data for each observation.

Historic USGS NAS FaST maps represent the potential spread of established, non-native aquatic species by flood waters at drainage divides one year after a major storm that occurred prior to 2017. Areas impacted by flooding are defined by 10-digit Hydrologic Unit Codes (HUC10) that contain flood elevation data, including high water marks and storm tide sensors, from the USGS Flood Event Viewer (stn.wim.usgs.gov/fev/). These data are compared to USGS Digital Elevation Model (DEM) data (www.usgs.gov/core-science-systems/ngp/3dep) at HUC10 boundaries to assess the potential inundation at drainage divides. Areas where flood heights are greater than DEM heights at drainage divides are labeled “connection points” where aquatic species may have a potential corridor for temporary movement. Observations of established populations from the USGS NAS database (nas.er.usgs.gov) are mapped in areas determined as impacted by flood waters. Each HUC10 within the flood-impacted area is labeled either as “present in the watershed” if the population was established prior to the flood being mapped or as “potential spread due to flooding” if that HUC10 shares a connection point on a drainage divide with a HUC10 that contains an established population of the same species. For validation of a species’ potential flood dispersal, established populations that were observed up to one year after a flood event are mapped as post-storm observations. These observations potentially arrived to that HUC10 by way of flood waters if they are new to that HUC10 and have a reasonable corridor by way of the mapped connection points.

Hydrologic units identified as being flooded and potentially connected as part of the historic USGS NAS FaST maps are determined based on the best available data. These maps may not include all flooded areas. The historic USGS NAS FaST maps focus on the potential spread of nonindigenous aquatic species between hydrologic units and are not maps of flood inundation.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [4/15/2024].

Contact us if you are using data from this site for a publication to make sure the data are being used appropriately and for potential co-authorship if warranted.

For general information and questions about the database, contact Wesley Daniel. For problems and technical issues, contact Matthew Neilson.