Weather Creates Dangerous Lake Currents - 07/22/13
If you're visiting the Lake Michigan shoreline Tuesday or Wednesday to do a little swimming, take note that weather conditions are expected to create dangerous rip currents near the shoreline. Rip currents are strong flows of water that run perpendicular to the shoreline. Swimmers caught in a rip are taken away from the beach, typically following their first instinct which is to fight the current by swimming toward shore. That's futile, even for the strongest swimmers. Energy sapped, the swimmer in the rip will drown if not first reached by rescuers.
Experts advise the two most important things to remember to survive/escape a rip current are 1) don't panic, and 2) swim parallel to the shoreline. It is virtually impossible for a swimmer to make significant progress against the rip, but swimming perpendicular to the current -- parallel to the beach -- will take him/her out of the current without expending excess energy fighting against it.
Perhaps an even better preventive measure is to know when and where rip currents are most likely, and avoid swimming in Lake Michigan when/where the threat is high. Tomorrow is one of those days. Rip tides frequently result from a disturbance in the typical wave pattern/motion of the water as it makes its way to shore. The disturbance causes the waves to break unevenly, which over time creates stronger currents of water that are moving away from the shore.
Disturbances can be caused by piers or breakwaters -- which is why it is a good idea for swimmers to stay a safe distance away from each -- and by strong winds, particularly when the winds are blowing at an angle toward the shoreline. Winds favorable for rip currents typically follow strong frontal boundary passages across West Michigan -- either a warm front bringing a strong southwesterly wind or a cold front ushering in a strong northwesterly wind. Tuesday, a potent cold front moves across our area followed by a strong northwesterly wind flow. It is that flow which is likely to cause rip currents to form near the shoreline of Lake Michigan. The threat remains through Wednesday, after which the wind and wave action are expected to diminish, returning the nearshore waters to safer swimming conditions.