Tommy Allsup performs during Friday evening's sock hop at the Surf Ballroom at Clear Lake. (Globe Gazette photo by Matt Foy) Dion DiMucci, whose claim of a coin toss with the late Ritchie Valens has fueled anger in some rock and roll corners.
In Maine (U.S.) low tide occurs roughly at moonrise and high tide with a high moon, corresponding to the simple gravity model of two tidal bulges; at most places however, moon and tides have a phase shift. mixed tide; two uneven tides a day, or one high and one low, is also possible. Tides vary on timescales ranging from hours to years due to a number of factors. To make accurate records, tide gauges at fixed stations measure the water level over time.
Two high tides occur each day, due to the gravitational pull on the  ocean generated by the moon. There are also two low tides in every  24-hour period.