August is the month when ocean swimming is at its best; the water has warmed enough to make long swims a pleasant escape from the heat and dust of summer. This is also the month when hurricanes and tropical storms can come barreling up the coast from the warmer waters south of us and kick up dangerous surf and rip currents, also known as riptides.

Lifeguards made a series of rescues this week at Lucy Vincent Beach in Chilmark, where rip currents have created unsafe swimming conditions in spots, Chilmark beach superintendent Martina Mastromonaco said yesterday. On Monday, two women were rescued by lifeguards after currents pulled them out to sea.

Ripples of Hurricane Frances left a tragic mark on a remote section of Chilmark's south shore Friday afternoon. A rip current is being blamed in the drowning death of a 58-year-old woman from Cambridge who was swimming with a friend.

Gwenneth Knight, a consultant to the Harvard University Art Museums on Indian and Islamic acquisitions, died Saturday after being airlifted to Brigham & Women's Hospital in Boston from the Martha's Vineyard Hospital.