The meteotsunami hazard is assessed in northern Lake Michigan from both short‐term and long‐term records of water level, wind speed, and air pressure. Cross‐wavelet analysis reveals that meteotsunamis can be caused by atmospheric disturbances that are pressure dominated, wind dominated, or both pressure and wind forced. In total, air pressure and wind stress are found to contribute similarly to meteotsunami initiation in northern Lake Michigan. The pressure‐driven meteotsunamis tend to be associated with convective storms, whereas meteotsunamis that are mainly wind‐driven are associated more with cyclonic‐type storms. The atmospheric disturbances responsible for largest meteotsunamis in northern Lake Michigan are found to have a propagation speed close to 32 m/s and from the south to north direction. A heuristic approach is developed to estimate the maximum meteotsunami height from the atmospheric disturbance strength and velocity. Overall, the heuristic approach is shown to be an effective methodology to assess the meteotsunami hazard over a wide range of potential atmospheric disturbance conditions.

A tragic drowning event occurred along southeastern beaches of Lake Michigan on a sunny and calm July 4, 2003, hours after a fast-moving convective storm had crossed the lake. Data forensics indicates that a moderate-height (~0.3 m) meteotsunami was generated by the fast-moving storm impacting the eastern coast of the lake. Detailed Nearshore Area (DNA) modeling forensics on a high-resolution spatial O(1 m) grid reveals that the meteotsunami wave generated unexpected rip currents, changing the nearshore condition from calm to hazardous in just a few minutes and lasting for several hours after the storm. Cross-comparison of rip current incidents and meteotsunami occurrence databases suggests that meteotsunamis present severe water safety hazards and high risks, more frequently than previously recognized. Overall, meteorological tsunamis are revealed as a new generation mechanism of rip currents, thus posing an unexpected beach hazard that, to date, has been ignored.

The role of meteorologically induced water level oscillations (MIWLOs) on bottom shear stresses in a freshwater estuary in the Great Lakes is investigated. Atmospheric data including air pressure, wind speed and direction, and radar reflectivity are compiled, and comprehensive field measurements including velocity profiles, water levels, river discharges, and bottom sediment properties in the Manistique River (MR) estuary, Michigan, are conducted. Wavelet and cross-wavelet analysis reveals that large velocity events (>0.5 m/s) in the MR estuary are generated by high-frequency MIWLOs (i.e., meteotsunamis and high-frequency seiches) induced by energetic oscillations in air pressure and/or wind speed and direction with periods below 2 hr. Measured velocity profiles reveal that MIWLO-dominated conditions can increase bottom shear stress by an order of magnitude in comparison with river-dominated flow conditions. The hydrodynamic model indicates that bottom shear stresses under both the downstream and upstream flows during the MIWLO-dominated event were significantly larger than those during river-dominated conditions. The interactions of MIWLOs and flood flows can significantly alter the bottom shear stresses in the main river channel, and MIWLOs are revealed to be the principal resuspension mechanism in areas such as the upstream tributary branches where flood flows individually do not cause resuspension. Furthermore, the role of MIWLOs asymmetry in fresh water Great Lakes estuaries on velocity residuals and net sediment transport is revealed and discussed. Overall, this paper fills important knowledge gaps in the role of MIWLOs on sediment transport in enclosed basin estuaries, thus providing essential information for coastal management and estuarine remediation.Seiches, one type of MIWLOs, are basin-scale standing waves frequently observed in an enclosed or semienclosed water body (As-Salek & Schwab, 2004; Bedford, 1992) and periods of waves are determined by