CONTACT: NOAA Chesapeake Bay Office FOR IMMEDIATE RELEASE Derek Orner 6/11/98 NOAA's National Ocean Service Dan Dewell
As hundreds of swimmers participate in the 4.4 mile Great Chesapeake Bay Swim for the March of Dimes on June 14, information collected by the National Oceanic and Atmospheric Administration about weather, water temperature, tides and currentswill help them meet the challenge more safely and assess the risks of the open-water swim.
Race organizers will use the NOAA information to confirm or adjust the late morning start time based on weather conditions Sunday morning. Swimmers and organizers will have the latest information on currents, wind, or any potential thunderstorms to help make the open-water swim as safe as possible.
The annual Great Chesapeake Bay Swim has drawn more than 600 swimmers in past years. Participants attempt to cross the Bay from Sandy Point State Park on the west to Kent Island on Maryland's Eastern Shore, swimming between the two spans of the Bay Bridge. Well-below-average water temperatures last year (62 degrees F) decreased the number of swimmers that completed the race. This year, water temperatures are expected to be about average (72 degrees F).
Since NOAA began providing advice on tidal currents for the race in 1993, swimmers have not had to contend with strong tidal currents like those experienced in 1991 and 1992. Only a few dozen of the approximately 550 swimmers per year were unable to complete the race between 1993 and 1996, when NOAA assisted with the timing of the start of the race. In 1997, 115 swimmers could not complete the race mostly due to the colder than normal water temperatures and choppy conditions.
NOAA's National Ocean Service has predicted slack current conditions at Sandy Point at about 11:00 a.m., the tentative race start time. Slack tide is when there are the slowest current speeds, occurring when the tidal current switches direction. The current will be switching direction from a flood to an ebb current over the course of the race. Most swimmers will be in the water traveling with the slack water as it crosses the Bay during the tide change. Some of the faster swimmers will feel the decreasing flood current and some of the slower swimmers will feel the increasing ebb current. NOAA's Chesapeake Bay Office is coordinating the agency information for the swimmers and race staff.
During three of the past five years, NOAA Chesapeake Bay Office personnel, with support from Maryland scientists and the National Ocean Service, conducted research cruises the day before the race to measure real-time current velocities, towing an Acoustic Doppler Current Profiler (ADCP). NOAA towed an ADCP in past years and observed the pattern of currents between Sandy Point and Kent Island during that part of the tidal cycle when the swim would be taking place. NOAA has found consistent patterns of slack tide every year: current changes direction on the Sandy Point shoreline first and the majority of the swimmers fortunately travel with the slack current as it moves eastward.
The NOAA Chesapeake Bay Office coordinates all of NOAA's Chesapeake Bay efforts with the multi-state/federal partnership known as the Chesapeake Bay Program, working to protect and restore the Chesapeake Bay. The NOAA Office will have a booth set up at the finish line to distribute information on bay tides, currents, weather and efforts to restore the Bay.