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Great Lakes Swim Season Summaries

Click a year to see the seasonal summaries, or read about the database and the 2002-2016 Data below

About the Great Lakes Current Incident Database

 

Each summer there are an average of 12 fatalities and 23 rescues due to dangerous currents on the Great Lakes (10 year average). The National Weather Service in Northern Indiana maintains the Great Lakes Current Incident Database (GLCID), a 15 year archive of current-related incidents. Case studies were completed on a total of 514 current-related incidents to learn about where and when dangerous currents form. This research improves National Weather Service beach forecasts and beach hazards statements. Victim demographics were also collected to improve beach safety outreach and education efforts. The Great Lakes see millions of visitors per year at State Parks alone, most within a 3-4 month period in the summer. The key to being safe is knowledge. Beachgoers and the water safety community need to understand how, why, where, and when dangerous currents form. 

It is important to realize that although there are many incidents that occur at these beaches, the number of incidents must be kept relative to how many people visit the beaches each year. For example, Indiana Dunes National Lakeshore has seen around 18 current related incidents since 2016, however over 2 million people visit the park EACH YEAR! Similarly, Ottawa County in Michigan has seen more than 100 incidents over the years, however they also see around 2 million visitors per year at Holland State Park alone. These beaches are all safe and fun to swim at, however beachgoers must remain alert to the changing weather and wave conditions and heed the advice of park patrol and lifeguards. 

 

Database History

In 1998, 12 year old Travis Brown drowned in a rip current at a Lake Michigan beach along US-2 in Mackinac County, Michigan. Prior to that incident, people didn't think rip currents could happen on the Great Lakes. In memory of Travis, the Brown Family started the Mackinac Water Safety Review team, which included Michigan Sea Grant, local law enforcement, and other members of the community. Eventually, they reached out to the National Weather Service in Marquette, Michigan to see if they could start a forecast on the Great Lakes to alert the public about dangerous waves and currents. One of the forecasters Dave Guenther (now retired) agreed to join the group, and get forecasts started on the Great Lakes. To learn about where, why, and when the currents developed, Dave started the Great Lakes Current Incident Database. Once Dave retired in January 2011, he handed the task to Megan Dodson, who now maintains the database from NWS Northern Indiana. Forecasts are now done at nearly all NWS Offices on the Great Lakes, and outreach has greatly improved as a result of the database. Thanks to a collaborative project with Coastal Zone Management and the Michigan Department of Environmental Quality, the database is available online. 

Searching the Database & Reporting an Incident

To search the database for more detailed information, click hereTo submit a current-related incident into the database, please use this form. Any incidents submitted using the form will be sent to Megan Dodson for review before being entered in. We accept incidents that occurred from 2002 to present. If you have any questions or concerns, get in touch with Mrs. Dodson at NWS Northern Indiana. 

About Swim Season Summaries

Each swim season, which runs from roughly May 1st to October 15th each year, NWS Northern Indiana writes up a summary of the incidents that occurred that year. This is usually posted on this page sometime in mid to late October, weather dependent. Statistics are updated within the actual database monthly during the summer. Seasonal summaries are usually posted between mid October and early November.

An Overview of Dangerous Currents on the Great Lakes (2002-2016)

There are several dangerous currents that can cause a swimmer to struggle on the Great Lakes. The currents that have most often claimed lives over the past 15 years (2002-2016) are structural currents, rip currents, outlet currents, longshore currents, and channel currents. According to the National Weather Service (NWS) Great Lakes Current Incident Database (GLCID), the Great Lakes averages around 11 drowning fatalities per year related to dangerous currents. Most of these dangerous current incidents occur on Lake Michigan because its eastern shores are positioned favorably for current development, and it is a popular tourist destination. Note that the incidents collected in the GLCID are current related, meaning currents may have been only a partial cause of the fatality or rescue (likely a combination of high waves and currents).To learn about the various types of currents, visit this webpage.

When Great Lakes current related incidents are analyzed, several commonalities emerge. First, a majority of the incidents occur during, or just after high wave action. Most of the wave periods during the incident were short, meaning there is less time in between each incoming wave (less time for swimmers to recover in between waves). Waves were likely an equal contributor in many of the incidents. Once a swimmer is pulled into deeper water by the current, the waves quickly become overwhelming. Secondly, most of the incidents occur near shoreline structures, such as a breakwall or pier.

 

Fig. 1. A graph of current related incidents from 2002-2016. The years of 2009, 2011, and 2012 were years where there was one day with greater than 18 rescues, which are marked by orange boxes in this graph. The swim season of 2016 had above average current related fatalities and rescues (2002-2013 average). Averages are marked by the light blue and dark green lines. GLCID (2016).

 

Current-Related Incidents By Lake

Lake Michigan has the most current related incidents of all the Great Lakes. This is because Lake Michigan (mainly the eastern shore) is favorably aligned for the weather and wave conditions conducive to current formation, and many beaches along the shoreline have sandbars and breakwalls. Additionally, Lake Michigan sees extensive tourism.

 

Fig. 2. Number of current-related incidents by Great Lake. "Incidents" include both rescues and fatalities. GLCID (2016).

 

Conditions that Lead to Dangerous Currents and High Wave Action

Dangerous currents develop at times when the winds (hence waves) are blowing in an onshore direction (towards the shore), and wave heights are moderate to high. This can be seen by looking at the data from the GLCID, where a majority of the time, waves were onshore or close to parallel to shore and wave heights were generally 3 feet or greater. High waves are conducive to currents because they 'pile up' the water near the beach, which causes the surface of the water to be uneven. Water can also 'pile up' near a shoreline structure, like a breakwall, or near a river mouth. The water must return into the lake or the ocean, so it flows outward as a rip current, structural current, or outlet current. Longer wave periods (the time in between each successive wave) also work to 'pile up' water near the beach. On the ocean, rip currents are typically associated with wave periods greater than 9 seconds, but can occur when wave periods are as short as 4 seconds. On the Great Lakes, most of the incidents occur when wave periods are 4 to 5 seconds, which is the average wave period on the Great Lakes (Fig. 5).

 

Fig. 3. Orientation of the winds (waves) relative to the shore during outward flowing current-related incidents (structural, rip, outlet). Waves moving onshore at a 60-90 degree angle will most often lead to rip currents, whereas waves moving onshore at a more oblique angle (especially 30-59 degrees) will produce primarily structural currents. Keep in mind, however, that 30-59 degree angle approaches can also lead to rip currents that develop more diagonally to shore (versus perpendicular to shore). Most of the incidents on the Great Lakes are caused by structural currents and rip currents, so it is reasonable that most of the waves are approaching the beach at more oblique angles. This graph removes data from days with greater than 18 rescues in one location so that it is not skewed. Data from the GLCID (2016).

 

Fig. 4. A majority of current related incidents occur during moderate to high wave action. Incidents decrease dramatically after 6 ft because most people are too intimidated to swim when waves are above their head. Data from the GLCID (2016).

 

Fig. 5. Wave periods during current related incidents on the Great Lakes. Wave periods are typically 4 to 5 seconds. Longer wave periods are more conducive to developing strong rip currents on the ocean and the Great Lakes. However, wave periods on the Great Lakes are fetch limited (limited by the distance the wind can travel across the lake), so periods are often less than 7 seconds. Data from the GLCID (2016).

 

Current Related Incidents on the Great Lakes

 

Fig. 6. Shows the number of current related incidents on the Great Lakes by county (for an interactive version, visit the main page). The prevailing wind directions over the Great Lakes are west, southwest, and northwest (Center, Fig. 7). This is why a majority of the incidents (seen as the darker red colors) are seen on the eastern, southern, and northern shores of each of the Lakes. These wind directions are often associated with the passage of a cold front (which causes winds to veer from southwest to northwest over a time period). With stronger winds out of these directions, waves can get high on the lakeshore, which can develop dangerous currents. An interactive version of this map can be found here. (GLCID, 2016).

 

Lake Michigan: Tourism + Favorable Conditions and Features for Current Development

Onshore directed winds and waves, shoreline structures, warm water and air temperatures, and popular tourist destinations all come together in late July-early August to bring higher numbers of incidents (rescues and fatalities) to the southeastern shore of Lake Michigan (Fig. 7). The most common pattern associated with current-related incidents on the Great Lakes, is the passage of a cold front because it often brings stronger onshore winds, and hence larger waves (Fig. 8). 

 

Fig. 7. The map on the left depicts the most common location for current related incidents (GLCID, 2002-2016). The middle map depicts the breakwalls (black rectangles) and the most common wind directions (red arrows) over Lake Michigan.  The breakwalls are not realistic in size/length-they were drawn large for easy visibility. The map on the right is the number of visitors to state and national parks in 2012. The combination of frequent favorable wind directions for current development, beach features (breakwalls, sandbars), and popularity cause Lake Michigan to have more incidents than all of the other Great Lakes.

 

Fig. 8. The most common pattern observed during current related incidents on the Great Lakes is the passage of a cold front. HP/LP stands for high and low pressure-where the pattern may have been such that the beach was in between both features. Does not include channel current related incidents (17 total). GLCID (2016).

 

It is important to realize that although there are many incidents that occur at these beaches, the number of incidents must be kept relative to how many people visit the beaches each year. For example, Indiana Dunes National Lakeshore has seen around 18 current related incidents since 2016, however over 2 million people visit the park EACH YEAR! Similarly, Ottawa County in Michigan has seen more than 100 incidents over the years, however they also see around 2 million visitors per year at Holland State Park alone. These beaches are all safe and fun to swim at, however beachgoers must remain alert to the changing weather and wave conditions and heed the advice of park patrol and lifeguards. If waves get to 3 feet or greater, dangerous currents are possible and visitors should stay out of the water. Additionally, visitors should always stay away from shoreline structures and river mouths, as dangerous currents often form there.

 

For references, click HERE.