'Catch the King' Tide

Let's map how far it floods...

Catch the King is the world's largest environmental survey. It leverages community science to aid in GPS flood data collection throughout coastal Virginia. Catch the King aims to map the king tide's maximum inundation extents with the goal of validating and improving predictive models for future forecasting of increasingly pervasive "nuisance" flooding. The project's current focus is centered on mapping inundation extents in coastal Virginia, within the automated mapping scope of VIMS' Tidewatch storm tide forecast map, but we welcome volunteers from outside of our present focus region who are willing and eager to contribute to this endeavor. Please sign up below!

  1. Volunteer Registration (so we can attempt to organize your flood mapping efforts): |
  2. Mobile App Registration (free on iOS & Android; use your phone's GPS to map floods): | 
  3. VIMS' Inundation Model Forecasts (help validate & improve future flood forecasts in VA): ( features VIMS' short- and long-term flood forecasts, and is run by the CCRM's open-source SCHISM Hydrodynamic Model)

{{youtube:large|-CpB3iI2b40, See Catch the King's Recent Media Coverage on The Weather Channel.}}

This year's Catch the King event focused on the highest predicted astronomical tide of 2022, the king tide, which took place on the morning of Saturday, October 29. This served as the annually scheduled dress-rehearsal for a coordinated volunteer network to learn how to map the flood extent of an inundation event using the GPS on their mobile device in preparation for more significant floods caused by hurricanes, nor'easters, heavy rainfall, and wind tides. Our veteran volunteer flood mappers also collected 1000's of data points during a couple of spring tides in April and May along with inundation impacts after Hurricane Ian in early October 2022. Annually, we've been mapping king tides since 2017, and here's what each Catch the King mapping event looked like:

Click on an interactive map above to compare flood extent observations with VIMS' model.


Did you hear about Catch the King on The Weather ChannelCBS This Morning, or NPR's Science Friday?

Looking to get involved and don't live in Virginia? Check out our video tutorial and PDF walkthrough to learn how to map flooding in a community near you! 

Each year, prior to the king tide flood event, Dr. Loftis at the CCRFR designs a webmap to direct volunteers to public places that are forecasted to flood during the king tide using VIMS' hydrodynamic models. Then, during the king tide, GPS data points are collected by many volunteers to effectively breadcrumb/trace the high water line. This approach is used each year to map flooding extents across coastal cities and counties in Virginia by pressing the 'Save Data' button in the 'Sea Level Rise' mobile application every few steps along the water's edge during annual king tides and after major storm events.

Catch the King's greater scientific aspiration involves using this information to validate VIMS' inundation models via calculated distance differences as demonstrated in the embedded video example below, and by inferred volume differentials, when GPS flood extent data are translated to lidar-derived digital elevation models. Community scientists' data are then used to correct elevations and hone spatially varying friction parameterization assumptions in VIMS' models to improve future inundation predictions. 

Click the photo for an example of how Catch the King data has helped improve the VIMS flood model.

Map of Past Catch the King Flood Monitoring Data

GPS high water mark data from past Catch the King tidal flood mapping events appear on the embedded map below as aggregated flood icons below to mark where volunteers have collected data during past king tide mapping events. These flood marker icons are shaded by year they were collected and are proportionally sized by the relative amount of data points they represent:

SLRiconforArcGIS Catch the King 2017
SLRiconforArcGISgreen.png Catch the King 2018
SLRSensorIcon2.png Catch the King 2019
slr icon for arcgis yellow Catch the King 2020
SLRiconpurple Catch the King 2021
Catch the King 2022

SLRiconpink Catch the King 2023

View Full Screen Map in New Window

This map is useful to illustrate mapping locations observed from past mapping events and to identify areas where there are gaps in previous years' observation efforts. Zoom in on the map to separate the aggregated points at each mapping site. If you wish to access Catch the King's GPS data as GIS shape files, they are available for download at these page links next to the icon legend above the map, by year.

Response from Catch the King's dedicated volunteers in 2017, fueled by constant media coverage leading up to the event, caused Catch the King to become the largest community science/crowdsourcing survey event in the world. Over 35 separate volunteer training events were held all over Hampton Roads resulting in 722 known participants collecting 59,718 time-stamped GPS maximum flooding extent measurements and 1,126 geotagged photographs of the king tide flooding during the 4-hour event. Click here for a map with an illustrative visual distribution of these statistics. Since 2017, over 200,000 GPS-reported high water marks and 4,000+ geolocated photographs have been collected by 1,000+ unique volunteers participating in Catch the King and other year-round flood mapping events.  

{{youtube:large|CTZKK1jM2i8, See Catch the King's Recent Media Coverage on CBS This Morning.}}

Catch the King is primarily sponsored by the Hampton Roads Sanitation District and AECOMWHRO Public Media is the lead media sponsor for Catch the King, and helps promotion the event as part of a year-round environmental education program for high school students. With a grant from the Hampton Roads Community Foundation and additional funding from the Batten Environmental Education Initiative, WHRO offers incentives to dozens of schools to join in its resilience education effort. Catch the King enables students to share in a project-based outdoor learning experience, utilizing smartphones in a way that’s educational and positive while contributing to a better understanding of the most central of challenges to Hampton Roads: sea level rise. Though this year’s focus will be on attracting more students, Catch the King organizers welcome all individuals and organizations to participate. Catch the King is grateful for the support of tHRive, the young professionals of the Hampton Roads Chamber. 

Catch the King is also made possible by the nonprofit groups, Wetlands Watch and Concursive Corp., creators and developers of the community-science Sea Level Rise app (iOS and Androidused in the event. Our science liaison is Dr. Derek Loftis of the Virginia Institute of Marine Science, whose work is funded in part by the Commonwealth Center for Recurrent Flooding Resiliency. Our volunteer coordinator is Gabi Kinney at Wetlands Watch. 

Data Archive

View all data Catch the King has collected through the Sea Level Rise App (by year)

Catalogue of Media Coverage of Catch the King by year:

  1. Catch the King 2022 Tidal Mapping Registration
    Cape Charles Mirror, Oct. 2, 2022 
  2. Citizen scientists conduct annual 'Catch the King' survey of sea level rise
    Bono Hererra, Oct. 30, 2022 

More to come...
See an article that should be included in this list? Please email it to me at

  1. Sea Level Rising More Rapidly: ‘Report Cards’
    Coastal Review, Feb 17, 2021  
  2. Contaminated water, land erosion, climate refugees: Historic Triangle, Tidewater regions could feel the secondary effects of coastal sea level rises
    Em Holter & Maggie More, Tidewater Review, Jun 11, 2021

  3. King Tides: Use the app to measure sea level rise
    Martin Ricker, Texas News Today, Sep 20, 2021 

  4. Norfolk’s “Super King Tide” Exceeds Flooding Predictions
    Kendall Osborne, Nov 8, 2021

  1. King Tides: Using an app to measure rising sea levels
    Brook Silva-Braga, CBS This Morning, Jan 4, 2020
  2. Using an app to measure rising sea levels
    CBS News, Jan 6, 2020 
  1. King Tides: Using an app to measure rising sea levels
    Chesapeake Research Consortium, Feb 11, 2019 
  2. As High-Tide Flooding Worsens, More Pollution Is Washing to the Sea
    Jim Morrison, Yale Environment 360, Mar 14, 2019
  3. Catch the King... the largest environmental survey on the planet
    Dave Mayfield and Derek Loftis, Catch the King, Tides that Bind, & VIMS, April 25, 2019 
  4. Catch the King sets an official Guinness world record
    Tamara Dietrich, Daily Press, April 25, 2019
  5. Catch the King Catches Guinness World Record
    David Mayfield, April 25, 2019
  6. Catch the King sets an official Guinness world record
    Tamara Dietrich, The Virginian-Pilot, April 25, 2019
  7. Catch the King Enters Guinness Record Books!
    Skip Stiles, April 25, 2019
  8. Catch the King catches Guinness World Record
    Virginia Gazette, April 25, 2019
  9. Hampton Roads Now Holds King Tide Guinness World Record
    Chesapeake Bay Magazine, April 26, 2019
  10. Catch the King Catches Guinness World Record
    David Malmquist, College of William & Mary, April 29, 2019
  11. Catch the King Earns a Guinness World Record
    Belinda Elliott, WHRO Public Media, April 30, 2019
  12. From Our Sponsors - Spring 2019
    Virginia Master Naturalists, May 2, 2019
  13. Embracing The Salt And Adapting To Sea Level Rise
    Ira Flatow, NPR Science Friday, May 17, 2019
  14. Community-scientists set to Catch the King again this weekend
    Tamara Dietrich, Daily Press, October 25, 2019
  15. King tide provides royal value
    David Malmquist, VIMS, October 29, 2019
  16. Catch the King racks up king tide data for a third year
    Tamara Dietrich, Daily Press, October 29, 2019 
  1. King Tide data shows Peninsula flooding in 50 years
    Tamara Dietrich, Daily Press, Jan. 23, 2018 
  2. How Virginia Beach involves citizens in disaster preparedness
    Nurfilzah Rohaidi, Gov Insider, Feb. 1, 2018 
  3. Podcast: King Tide (Segment: 28:00 - 46:30): 
    Cathy Lewis, WHRO, HearSay with Cathy Lewis, Feb. 1, 2018
  4. Are You Ready to “Catch the King?”
    Madeline Carey, WHRO, Aug. 1, 2018
  5. Hampton Roads is invited to 'Catch the King' ... again
    Tamara Dietrich, Daily Press, Aug. 31, 2018 
  6. Reck on the Road: Catch The King
    Chris Reckling, WAVY TV10, Norfolk, Sep. 25, 2018 
  7. Hampton Roads is invited to 'Catch the King' ... again
    The Virginian-Pilot Editorial Board, Sep. 28, 2018 
  8. Help 'Catch the King' and join a regional effort to measure astronomical tide
    City of Hampton Civic Alert, Oct. 5, 2018 
  9. Hundreds to help map flooding at this year's Catch the King event 
  10. Student installs tide gauges in Hampton for community scientists to help create 3D flood map
    Tamara Dietrich, Daily Press, Oct. 26, 2018
  11. It's time to Catch the King tide again
    Tamara Dietrich, , Oct. 26, 2018
  12. Community scientists throughout Hampton Roads turn out to Catch the King
  13. Volunteers map the King Tide in Norfolk
    Steven Graves, WVEC, Oct. 27, 2017
  14. Mapping the King Tide
    Gloucester Mathews Gazette-Journal, Oct. 31, 2018
  1. Catch the King: A King Tide Mapping Event, November 2017
    Dave Mayfield, The Virginian-Pilot, and Derek Loftis, Commonwealth Center for Recurrent Flooding Resiliency, VIMS, W&M, Aug. 6, 2017 
  2. Regional Flood Mapping Event Uses "Sea Level Rise" Phone App
    Skip Stiles, Wetlands Watch, Aug. 10, 2017 
  3. "Catch the King" Tide Monitoring Event
    Lizz Gunnufsen, City of Chesapeake, Aug. 29, 2017 
  4. “How are we going to pay for this?” agencies ask re: climate change costs?
    Wes Siler, Rapid Shift, Sep. 11, 2017
  5. Hampton Roads media, scientists are teaming up to understand tides. We need your help.
    Daily Press & The Virginian-Pilot, Sep. 14, 2017
  6. An astronomical high tide will hit Hampton Roads on Nov. 5 -- will you help us Catch the King tide?
    Dave Mayfield, The Virginian-Pilot, Sep. 14, 2017
  7. A few questions and answers about Catch the King
    Dave Mayfield, The Virginian-Pilot, Sep. 14, 2017 
  8. VIMS Contributes to ‘King Tide’ Mapping Project
    David Malmquist, VIMS, Sep. 17, 2017 
  9. Will You "Catch the King"?
    Nicole Alvarado, Military News, Sep. 17, 2017 
  10. 'King Tide' mapping project
    David Malmquist, VIMS, Science Daily, Sep. 18, 2017 
  11. Scientists Seek Community Help to Map Nov. 5 King Tide Sea Levels
    Laurie L. Dove, How Stuff Works, Sep. 25, 2017 
  12. Learn how to 'Catch the King' Tide
    Kate Mishkin, Daily Press, Sep. 26, 2017
  13. Catch the King Tide in Hampton Roads
    Belinda Elliott, WHRO Education, Sep. 26, 2017 
  14. Volunteers Learn Tips, Tricks to Measure King Tide
    Kate Mishkin, Daily Press, Sep. 28, 2017 
  15. Calling All Hampton Roads Residents to Help Catch the King Tide
    Daniel Kvaternik, City of Newport News, Sep. 29, 2017 
  16. New App to Document King Tide Flooding in Hampton Roads
    Chesapeake Bay Magazine, Oct. 2, 2017 
  17. What is the King Tide? Hampton Roads' highest astronomical tide of the year!
    Yasmeen Freightman, WVEC, Oct. 11, 2017
  18. Catching the King Tide in Hampton Roads
    The Virginian-Pilot Editorial Board, Oct. 15, 2017
  19. Why King Tides Are Flooding Coastal Cities More Often
    John Perritano,, Oct. 17, 2017
  20. Four newsrooms, 350 volunteers ready to engage Virginians on sea's rise
    Ashley McBride, Poynter, Oct. 17, 2017
  21. King Tide volunteer sign-up ends Sunday
    Tamara Dietrich, Daily Press, Oct. 20, 2017 
  22. Help Document Sea Level During King Tide Event Nov 4-6
    Jacques Cousteau National Estuarine Research Reserve, Oct. 22, 2017 
  23. King Tide: Help scientists 'Catch the King'
    Arrianee LeBeau, WVEC, Oct. 30, 2017
  24. King Tide offers York County school real-world teaching opportunity
    Josh Reyes, Daily Press, Nov. 1, 2017 
  25. Mild weather, flooded streets: Ideal conditions to Catch the King
    Dave Mayfield, The Virginian-Pilot, Nov. 3, 2017 
  26. Hundreds of volunteers turn out to Catch the King tide
    Dave Mayfield, The Virginian-Pilot, Nov. 5, 2017 
  27. Peninsula volunteers catch the king tide
    Tamara Dietrich, Daily Press, Nov. 5, 2017 
  28. Four things we learned from tracing the king tide across Hampton Roads
    Dave Mayfield, The Virginian-Pilot, Nov. 7, 2017 
  29. An App and Volunteer Army Are Improving Local Tidal Flood Forecasts
    Jessica Leber, News Deeply, Dec. 1, 2017
  30. An App is Improving Local Tidal Flood Forecasts
    Ocean Leadership, Dec. 8, 2017 
  31. Reporters, Scientists, and Citizens Team to Map Virginia’s Highest Tide
    Dawn Wright, ESRI Blog, Dec. 13, 2017